Unwritten rules for fans and media

There seems to be an unwritten rule in baseball – not on the field, but in the stands, at home, in the press box, etc.

“You can’t criticize a manager’s decision if it doesn’t directly affect the outcome of the game, if it appears to ‘work’, or if the team goes on to win the game despite the decision.”

That’s ridiculous of course. The outcome of a decision or the game has nothing to do with whether the decision was correct or not. Some decisions may raise or lower a team’s chances of winning from 90% and other decisions may affect a baseline of 10 or 15%.

If decision A results in a team’s theoretical chances of winning of 95% and decision A, 90%, obviously A is the correct move. Choosing B would be malpractice. Equally obvious is if manager chooses B, an awful decision, he is still going to win the game 90% of the time, and based on the “unwritten rule” we rarely get to criticize him. Similarly, if decision A results in a 15% win expectancy (WE) and B results in 10%, A is the clear choice, yet the team still loses most of the time and we get to second guess the manager whether he chooses A or B. All of that is silly and counter-productive.

If your teenager drives home drunk yet manages to not kill himself or anyone else, do you say nothing because “it turned out OK?” I hope not. In sports, most people understand the concept of “results versus process” if they are cornered into thinking about it, but in practice, they just can’t bring themselves to accept it in real time. No one is going to ask Terry Collins in the post-game presser why he didn’t pinch hit for DeGrom in the 6^th inning – no one. The analyst – a competent one at least – doesn’t give a hoot what happened after that. None whatsoever. He looks at a decision and if it appears questionable at the time, he tries to determine what the average consequences are – with all known data at the time the decision is made – with the decision or with one or more alternatives. That’s it. What happens after that is irrelevant to the analyst. For some reason this is a hard concept for the average fan – the average person – to apply. As I said, I truly think they understand it, especially if you give obvious examples, like the drunk driving one. They just don’t seem to be able to break the “unwritten rule” in practice. It goes against their grain.

Well, I’m an analyst and I don’t give a flying ***k whether the Mets won, lost, tied, or Wrigley Field collapsed in the 8^th inning. The “correctness” of the decision to allow DeGrom to hit or not in the top of the 6^th, with runners on second and third, boiled down to this question and this question only:

“What is the average win expectancy (WE) of the Mets with DeGrom hitting and then pitching some number of innings and what is the average WE with a pinch hitter and someone else pitching in place of DeGrom?”

Admittedly the gain, if there is any, from making the decision to bring in a PH and reliever or relievers must be balanced against any known or potential negative consequences for the Mets not related to the game at hand. Examples of these might be: 1) limiting your relief possibilities in the rest of the series or the World Series. 2) Pissing off DeGrom or his teammates for taking him out and thus affecting the morale of the team.

I’m fine with the fans or the manager and coaches including these and other considerations in their decision. I am not fine with them making their decision not knowing how it affects the win expectancy of the game at hand, since that is clearly the most important of the considerations.

My guess is that if we asked Collins about his decision-making process, and he was honest with us, he would not say, “Yeah, I knew that letting him hit would substantially lower our chances of winning the game, but I also wanted to save the pen a little and give DeGrom a chance to….” I’m pretty sure he thought that with DeGrom pitching well (which he usually does, by the way – it’s not like he was pitching well-above his norm), his chances of winning were better with him hitting and then pitching another inning or two.

At this point, and before I get into estimating the WE of the two alternatives facing Collins, letting DeGrom hit and pitch or pinch hitting and bringing in a reliever, I want to discuss an important concept in decision analysis in sports. In American civil law, there is a thing called a summary judgment. When a party in a civil action moves for one, the judge makes his decision based on the known facts and assuming controversial facts and legal theories in a light most favorable to the non-moving party. In other words, if everything that the other party says is true is true (and is not already known to be false) and the moving party would still win the case according to the law, then the judge must accept the motion and the moving party wins the case without a trial.

When deciding whether a particular decision was “correct” or not in a baseball game or other contest, we can often do the same thing in order to make up for an imperfect model (which all models are by the way). You know the old saw in science – all models are wrong, but some are useful. In this particular instance, we don’t know for sure how DeGrom will pitch in the 6^th and 7^th innings to the Cubs order for the 3^rd time, we don’t know for how much longer he will pitch, we don’t know how well DeGrom will bat, and we don’t know who Collins can and will bring in.

I’m not talking about the fact that we don’t know whether DeGrom or a reliever is going to give up a run or two, or whether he or they are going to shut the Cubs down. That is in the realm of “results-based analysis” and I‘ve already explained how and why that is irrelevant. I’m talking about what is DeGrom’s true talent, say in runs allowed per 9 facing the Cubs for the third time, what is a reliever’s or relievers’ true talent in the 6^th and 7^th, how many innings do we estimate DeGrom will pitch on the average if he stays in the game, and what is his true batting talent.

Our estimates of all of those things will affect our model’s results – our estimate of the Mets’ WE with and without DeGrom hitting. But what if we assumed everything in favor of keeping DeGrom in the game – we looked at all controversial items in a light most favorable to the non-moving party – and it was still a clear decision to pinch hit for him? Well, we get a summary judgment! Pinch hitting for him would clearly be the correct move.

There is one more caveat. If it is true that there are indirect negative consequences to taking him out – and I’m not sure that there are – then we also have to look at the magnitude of the gain from taking him out and then decide whether it is worth it. In order to do that, we have to have some idea as to what is a small and what is a large advantage. That is actually not that hard to do. Managers routinely bring in closers in the 9^th inning with a 2-run lead, right? No one questions that. In fact, if they didn’t – if they regularly brought in their second or third best reliever instead, they would be crucified by the media and fans. How much does bringing in a closer with a 2-run lead typically add to a team’s WE, compared to a lesser reliever? According to The Book, an elite reliever compared to an average reliever in the 9^th inning with a 2-run lead adds around 4% to the team’s WE. So we know that 4% is a big advantage, which it is.

That brings up another way to account for the imperfection of our models. The first way was to use the “summary judgment” method, or assume things most favorable to making the decision that we are questioning. The second way is to simply estimate everything to the best of our ability and then look at the magnitude of the results. If the difference between decision A and B is 4%, it is extremely unlikely that any reasonable tweak to the model will change that 4% to 0% or -1%.

In this situation, whether we assume DeGrom is going to pitch 1.5 more innings or 1.6 or 1.4, it won’t change the results much. If we assume that DeGrom is an average hitting pitcher or a poor one, it won’t change the result all that much. If we assume that the “times through the order penalty” is .25 runs or .3 runs per 9 innings, it won’t change the results much. If we assume that the relievers used in place of DeGrom have a true talent of 3.5, 3.3, 3.7, or even 3.9, it won’t change the results all that much. Nothing can change the results from 4% in favor of decision A to something in favor of decision B. 4% is just too much to overcome even if our model is not completely accurate. Now, if our results assuming “best of our ability estimates” for all of these things yield a 1% advantage for choosing A, then it is entirely possible that B is the real correct choice and we might defer to the manager in case he knows some things that we don’t or we simply are mistaken in our estimates or we failed to account for some important variable.

Let’s see what the numbers say, assuming “average” values for all of these relevant variables and then again making reasonable assumptions in favor of allowing DeGrom to hit (assuming that pinch hitting for him appears to be correct).

What is the win expectancy with DeGrom batting. We’ll assume he is an average-hitting pitcher or so (I have heard that he is a poor-hitting pitcher). An average pitcher’s batting line is around 10% single, 2% double or triple, .3% HR, 4% BB, and 83.7% out. The average WE for an average team leading by 1 run in the top of the 6^th, with runners on second and third, 2 outs, and a batter with this line, is…..

63.2%.

If DeGrom were an automatic out, the WE would be 59.5%. That is the average WE leading off the bottom of the 6^th with the visiting team winning by a run. So an average pitcher batting in that spot adds a little more than 3.5% in WE. That’s not wood. What if DeGrom were a poor hitting pitcher?

Whirrrrr……

62.1%.

So whether DeGrom is an average or poor-hitting pitcher doesn’t change the Mets’ WE in that spot all that much. Let’s call it 63%. That is reasonable. He adds 3.5% to the Mets’ WE compared to an out.

What about a pinch hitter? Obviously the quality of the hitter matters. The Mets have some decent hitters on the bench – notably Cuddyer from the right side and Johnson from the left. Let’s assume a league-average hitter. Given that, the Mets’ WE with runners on second and third, 2 outs, and a 1-run lead, is 68.8%. A league-average hitter adds over 9% to the Mets’ WE compared to an out. The difference between DeGrom as a slightly below-average hitting pitcher and a league-average hitter is 5.8%. That means, unequivocally, assuming that our numbers are reasonably accurate, that letting DeGrom hit cost the Mets almost 6% in their chances of winning the game.

That is enormous of course. Remember we said that bringing in an elite reliever in the 9^th of a 2-run game, as compared to a league-average reliever, is worth 4% in WE. You can’t really make a worse decision as a manager than reducing your chances of winning by 5.8%, unless you purposely throw the game. But, that’s not nearly the end of the story. Collins presumably made this decision thinking that DeGrom pitching the 6^th and perhaps the 7^th would more than make up for that. Actually he’s not quite thinking, “Make up for that.” He is not thinking in those terms. He does not know that letting him hit “cost 5.8% in win expectancy” compared to a pinch hitter. I doubt that the average manager knows what “win expectancy” means let alone how to use it in making in-game decisions. He merely thinks, “I really want him to pitch another inning or two, and letting him hit is a small price to pay,” or something like that.

So how much does he gain by letting him pitch the 6^th and 7^th rather than a reliever. To be honest it is debatable whether he gains anything at all. Not only that, but if we look back in history to see how many innings starters end up pitching, on the average, in situations like that, we will find that it is not 2 innings. It is probably not even 1.5 innings. He was at 82 pitches through 5. He may throw 20 or 25 pitches in the 6^th (like he did in the first), in which case he may be done. He may give up a base runner or two, or even a run or two, and come out in the 6^th, perhaps before recording an out. At best, he pitches 2 more innings, and once in a blue moon he pitches all or part of the 8^th I guess (as it turned out, he pitched 2 more effective innings and was taken out after seven). Let’s assume 1.5 innings, which I think is generous.

What is DeGrom’s expected RA9 for those 2 innings? He has pitched well thus far but not spectacularly well. In any case, there is no evidence that pitching well through 5 innings tells us anything about how a pitcher is going to pitch in the 6^th and beyond. What is DeGrom’s normal expected RA9? Steamer, ZIPS and my projection systems say about 83% of league-average run prevention. That is equivalent to a #1 or #2 starter. It is equivalent to an elite starter, but not quite the level of the Kershaw’s, Arrieta’s, or even the Price’s or Sale’s. Obviously he could turn out to be better than that – or worse – but all we can do in these calculations and all managers can do in making these decisions is use the best information and the best models available to estimate player talent.

Then there is the “times through the order penalty.” There is no reason to think that this wouldn’t apply to DeGrom in this situation. He is going to face the Cubs for the third time in the 6^th and 7^th innings. Research has found that the third time through the order a starter’s RA9 is .3 runs worse than his overall RA9. So a pitcher who allows 83% of league average runs allows 90% when facing the order for the 3^rd time. That is around 3.7 runs per 9 innings against an average NL team.

Now we have to compare that to a reliever. The Mets have Niese, Robles, Reed, Colon, and Gilmartin available for short or long relief. Colon might be the obvious choice for the 6^th and 7^th inning, although they surely could use a combination of righties and lefties, especially in very high leverage situations. What do we expect these relievers’ RA9 to be? The average reliever is around 4.0 to start with, compared to DeGrom’s 3.7. If Collins uses Colon, Reed, Niese or some combination of relievers, we might expect them to be better than the average NL reliever. Let’s be conservative and assume an average, generic reliever for those 1.5 innings.

How much does that cost the Mets in WE? To figure that, we take the difference in run prevention between DeGrom and the reliever(s), multiply by the game leverage and convert it into WE. The difference between a 3.7 RA9 and a 4.0 RA9 in 1.5 innings is .05 runs. The average expected leverage index in the 6^th and 7^th innings where the road team is up by a run is around 1.7. So we multiply .05 by 1.7 and convert that into WE. The final number is .0085, or less than 1% in win expectancy gained by allowing DeGrom to pitch rather than an average reliever.

That might shock some people. It certainly should shock Collins, since that is presumably his reason for allowing DeGrom to hit – he really, really wanted him to pitch another inning or two. He presumably thought that that would give his team a much better chance to win the game as opposed to one or more of his relievers. I have done this kind of calculation dozens of times and I know that keeping good or even great starters in the game for an inning or two is not worth much. For some reason, the human mind, in all its imperfect and biased glory, overestimates the value of 1 or 2 innings of a pitcher who is “pitching well” as compared to an “unknown entity” (of course we know the expected performance of our relievers almost as well as we know the expected performance of the starter). It is like a manager who brings in his closer in a 3-run game in the 9^th. He thinks that his team has a much better chance of winning than if he brings in an inferior pitcher. The facts say that he is wrong, but tell that to a manager and see if he agrees with you – he won’t. Of course, it’s not a matter of opinion – it’s a matter of fact.

Do I need to go any further? Do I need to tweak the inputs? Assuming average values for the relevant variables yields a loss of over 5% in win expectancy by allowing DeGrom to hit. What if we knew that DeGrom were going to pitch two more innings rather than an average of 1.5? He saves .07 runs rather than .05 which translates to 1.2% WE rather than .85%, which means that pinch hitting for him increases the Mets’ chances of winning by 4.7% rather than 5.05%. 4.7% is still an enormous advantage. Reducing your team‘s chances of winning by 4.7% by letting DeGrom hit is criminal. It’s like pinch hitting Jeff Mathis for Mike Trout in a high leverage situation – twice!

What about if our estimate of DeGrom’s true talent is too conservative? What if he is as good as Kershaw and Arrieta? That’s 63% of league average run prevention or 2.6 RA9. Third time through the order and it’s 2.9. The difference between that and an average reliever is 1.1 runs per 9, which translates to a 3.1% WE difference in 1.5 innings. So allowing Kershaw to hit in that spot reduces the Mets chances of winning by 2.7%. That’s not wood either.

What if the reliever you replaced DeGrom with was a replacement level pitcher – the worst pitcher in the major leagues? He allows around 113% league average runs, or 4.6 RA9. Difference between DeGrom and him for 1.5 innings? 2.7% for a net loss of 3.1% by letting him hit rather than pinch hitting for him and letting the worst pitcher in baseball pitch the next 1.5 innings? If you told Collins, “Hey genius, if you pinch hit for Degrom and let the worst pitcher in baseball pitch for another inning and a half instead of DeGrom, you will increase your chances of winning by 3.1%,” what do you think he would say?

What if DeGrom were a good hitting pitcher? What if….?

You should be getting the picture. Allowing him to hit is so costly, assuming reasonable and average values for all the pertinent variables, that even if we are missing something in our model, or some of our numbers are a little off – even if assume everything in the best possible light of allowing him to hit – the decision is a no-brainer in favor of a pinch hitter.

If Collins truly wanted to give his team the best chance of winning the game, or in the vernacular of ballplayers, putting his team in the best position to succeed, the clear and unequivocal choice was to lift DeGrom for a pinch hitter. It’s too bad that no one cares because the Mets ultimately won the game, which they were going to do at least 60% of the time anyway, regardless of whether Collins made the right or wrong decision.

The biggest loser, other than the Cubs, is Collins (I don’t mean he is a loser, as in the childish insult), because every time you use results to evaluate a decision and the results are positive, you deprive yourself of the opportunity to learn a valuable lesson. In this case, the analysis could have and should have been done before the game even started. All managers should know the importance of bringing in pinch hitters for pitchers in high leverage situations in important games, no matter how good the pitchers are or how well they are pitching in the game so far. Maybe someday they will.

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Siegrest, platoon splits, and Joe Maddon

Last night in the Cubs/Cardinals game, the Cardinals skipper took his starter, Lackey, out in the 8^th inning of a 1-run game with one out, no one on base and lefty Chris Coghlan coming to the plate. Coghlan is mostly a platoon player. He has faced almost four times as many righties in his career than lefties. His career wOBA against righties is a respectable .342. Against lefties it is an anemic .288. I have him with a projected platoon split of 27 points, less than his actual splits, which is to be expected as platoon splits in general get heavily regressed toward the mean, because they tend to be laden with noise for two reasons: One, the samples are rarely large because you are comparing performance against righties to performance against lefties and the smaller of the two tends to dominate the effective sample size – in Coghlan’s case, he has faced only 540 lefties in his entire 7-year career, less than the number of PA a typical  full-time batter gets in one season. Two, there is not much of a spread in platoon talent among both batters and pitchers. The less spread in talent for any statistic, the more the differences you see among players, especially in small samples, are noise. Sort of like DIPS for pitchers.

Anyway, even with a heavy regression, we think that Coghlan has a larger than average platoon split for a lefty and the average lefty split tends to be large. You typically would not want him facing a lefty in that situation. That is especially true when you have a very good and fairly powerful right-handed bat on the bench – Jorge Soler. Soler has a reverse career platoon split, but with only 114 PA versus lefties, that number is almost meaningless. I estimate his actual platoon split to be 23 points, a little less than the average righty. For RHB, there is always a heavy regression of actual platoon splits, regardless of the sample size (while the greater the sample of actual PA versus lefties, the less you regress, it might be a 95% regression for small samples and an 80% regression for large samples – either way, large) simply because there is not a very large spread of talent among RHB. If we look at the actual splits for all RHB over many, many PA, we see a narrow range of results. In fact, there is virtually no such thing as a RHB with true reverse platoon splits.

Soler seems to be the obvious choice,  so of course that’s what Maddon did – he pinch hit for Coghlan with Soler, right? This is also a perfect opportunity since Matheny cannot counter with a RHP – Siegrest has to pitch to at least one batter after entering the game. Maddon let Coghlan hit and he was easily dispatched by Siegrest 4 pitches later. Not that the result has anything to do with the decision by Matheny or Maddon. It doesn’t. Matheny’s decision to bring in Siegrest at that point in time was rather curious too, if you think about it. Surely he must have assumed that Maddon would bring in a RH pinch hitter. So he had to decide whether to pitch Lackey against Coghlan or Siegrest against a right handed hitter, probably Soler. Plus, the next batter, Russell, is another righty. It looks like he got extraordinarily lucky when Maddon did what he did – or didn’t do – in letting Coghlan bat. But that’s not the whole story…

Siegrest may or may not be your ordinary left-handed pitcher. What if Siegrest actually has reverse splits? What if we expect him to pitch better against right handed batters and worse against left-handed batters?  In that case, Coghlan might actually be the better choice than Soler even though he doesn’t often face lefty pitchers. When a pitcher has reverse splits – true reverse splits – we treat him exactly like a pitcher of the opposite hand.  It would be exactly like Coghlan or Soler were facing a RHP. Or maybe Siegrest has no splits – i.e. RH and LH batters of equal overall talent perform about the same. Or very small platoon splits compared to the average left-hander? So maybe hitting Coghlan or Soler is a coin flip.

It might also have been correct for Matheny to bring in Siegrest no matter who he was going to face, simply because Lackey, who is arguably a good but not great pitcher, was about to face a good lefty hitter for the third time – not a great matchup. And if Siegrest does indeed have very small splits either positive or negative, or no splits at all, that is a perfect opportunity to bring him in, and not care whether Maddon leaves Coghlan in or pinch hits Soler. At the same time, if Maddon things that Siegrest has significant reverse splits, he can leave in Coghlan, and if he thinks that the lefty pitcher has somewhere around a neutral platoon split, he can still leave Coghlan in and save Soler for another pinch hit opportunity. Of course, if he thinks that Siegrest is like your typical lefty pitcher, with a 30 point platoon split, then using Coghlan is a big mistake.

So how do managers determine what a pitcher’s true or expected (the same thing) platoon split is? The typical troglodyte will use batting average against during the season in question. After all, that’s what you hear ad-nauseam from the talking heads on TV, most of them ex-players or even ex-managers. Even the slightly informed fan knows that batting average against for a pitcher is worthless stat in and of itself (what, walks don’t count, and a HR is the same as a single?), especially in light of DIPS. The slightly more informed fan also knows that one season splits for a batter or pitcher are not very useful for the reasons I explained above.

If you look at Siegrest’s BA against splits for 2015, you will see .163 versus RHB and .269 versus LHB. Cue the TV commentators: “Siegrest is much better against right-handed batters than left-handed ones.” Of course, is and was are very different things in this context and with respect to making decisions like Matheny and Maddon did. The other day David Price was a pretty mediocre to poor pitcher. He is a great pitcher and you would certainly be taking your life into your hands if you treated him like a mediocre to poor pitcher in the present. Kershaw was a poor pitcher in the playoffs…well, you get the idea. Of course, sometimes, was is very similar to is. It depends on what we are talking about and how long the was was, and what the was actually is.

Given that Matheny is not considered to be such an astute manager when it comes to data-driven decisions, it may be is surprising that he would bring in Siegrest to pitch to Coghlan knowing that Siegrest has an enormous reverse BA against split in 2015. Maybe he was just trying to bring in a fresh arm – Siegrest is a very good pitcher overall. He also knows that the lefty is going to have to pitch to the next batter, Russell, a RHB.

What about Maddon? Surely he knows better than to look at such a garbage stat for one season to inform a decision like that. Let’s use a much better stat like wOBA and look at Siegrest’s career rather than just one season. Granted, a pitcher’s true platoon splits may change from season to season as he changes his pitch repertoire, perhaps even arm angle, position on the rubber, etc. Given that, we can certainly give more weight to the current season if we like. For his career, Siegrest has a .304 wOBA against versus LHB and .257 versus RHB. Wait, let me double check that. That can’t be right. Yup, it’s right. He has a career reverse wOBA split of 47 points! All hail Joe Maddon for leaving Coghlan in to face essentially a RHP with large platoon splits! Maybe.

Remember how in the first few paragraphs I talked about how we have to regress actual platoon splits a lot for pitchers and batters, because we normally don’t have a huge sample and because there is not a great deal of spread among pitchers with respect to true platoon split talent? Also remember that what we, and Maddon and Matheny, are desperately trying to do is estimate Siegrest’s true, real-life honest-to-goodness platoon split in order to make the best decision we can regarding the batter/pitcher matchup. That estimate may or may not be the same as or even remotely similar to his actual platoon splits, even over his entire career. Those actual splits will surely help us in this estimate, but the was is often quite different than the is.

Let me digress a little and invoke the ole’ coin flipping analogy in order to explain how sample size and spread of talent come into play when it comes to estimating a true anything for a player – in this case platoon splits.

Note: If you want you can skip the “coins” section and go right to the “platoon” section. 

Coins

Let’s say that we have a bunch of fair coins that we stole from our kid’s piggy bank. We know of course that each of them has a 50/50 chance of coming up head or tails in one flip – sort of like a pitcher with exactly even true platoon splits. If we flip a bunch of them 100 times, we know we’re going to get all kinds of results – 42% heads, 61% tails, etc. For the math inclined, if we flip enough coins the distribution of results will be a normal curve, with the mean and median at 50% and the standard deviation equal to the binomial standard deviation of 100 flips, which is 5%.

Based on the actual results of 100 flips of any of the coins, what would you estimate the true heads/tails percentage of that coin? If one coin came up 65/35 in favor of heads, what is your estimate for future flips? 50% of course. 90/10? 50%. What if we flipped a coin 1000 or even 5000 times and it came up 55% heads and 45% tails? Still 50%. If you don’t believe or understand that, stop reading and go back to whatever you were doing. You won’t understand the rest of this article. Sorry to be so blunt.

That’s like looking at a bunch of pitchers platoon stats and no matter what they are and over how many TBF, you conclude that the pitcher really has an even split and what you observed is just noise. Why is that? With the coins it is because we know beforehand that all the coins are fair (other than that one trick coin that your kid keeps for special occasions). We can say that there is no “spread in talent” among the coins and therefore regardless of the result of a number of flips and regardless of how many flips, we regress the result 100% of the way toward the mean of all the coins, 50%, in order to estimate the true percentage of any one coin.

But, there is a spread of talent among pitcher and batter platoon splits. At least we think there is. There is no reason why it has to be so. Even if it is true, we certainly can’t know off the top of our head how much of a spread there is. As it turns out, that is really important in terms of estimating true pitcher and batter splits. Let’s get back to the coins to see why that is. Let’s say that we don’t have 100% fair coins. Our sly kid put in his piggy bank a bunch of trick coins, but not really, really tricky. Most are still 50/50, but some are 48/52, 52/48, a few less are 45/55, and 1 or 2 are 40/60 and 60/40. We can say that there is now a spread of “true coin talent” but the spread is small. Most of the coins are still right around 50/50 and a few are more biased than that.  If your kid were smart enough to put in a normal distribution of “coin talent,” even one with a small spread, the further away from 50/50, the fewer coins there are.  Maybe half the coins are still fair coins, 20% are 48/52 or 52/48, and a very, very small percentage are 60/40 or 40/60.  Now what happens if we flip a bunch of these coins?

If we flip them 100 times, we are still going to be all over the place, whether we happen to flip a true 50/50 coin or a true 48/52 coin. It will be hard to guess what kind of a true coin we flipped from the result of 100 flips. A 50/50 coin is almost as likely to come up 55 heads and 45 tails as a coin that is truly a 52/48 coin in favor of heads. That is intuitive, right?

This next part is really important. It’s called Bayesian inference, but you don’t need to worry about what it’s called or even how it technically works. It is true that if you flipped a coin and got 60/40 heads that that coin was much more likely to be a true 60/40 coin than it is to be a 50/50 coin. That should be obvious too.  But here’s the catch. There are many, many more 50/50 coins in your kid’s piggy bank than there are 60/40. Your kid was smart enough to put in a normal distribution of trick coins.

So even though it seems like if you flipped a coin 100 times and got 60/40 heads, it is more likely you have a true 60/40 coin than a true 50/50 coin, it isn’t. It is much more likely that you have a 50/50 coin that got “heads lucky” than a true 60/40 coin that landed on the most likely result after 100 flips (60/40) because there are many more 50/50 coins in the bank than 60/40 coins – assuming a somewhat normal distribution with a small spread.

Here is the math: The chances of a 50/50 coin coming up exactly 60/40 is around .01. Chances of a true 60/40 coin coming up 60/40 is 8 times that amount, or .08. But, if there are 8 times as many 50/50 coins in your piggy bank as 60/40 coins, then the chances of your 60/40 coin being a fair coin or a 60/40 biased coin is only 50/50. If there 800 times more 50/50 coins than 60/40 coins in your bank, as there is likely to be if the spread of coin talent is small, then it is 100 times more likely that you have a true 50/50 coin than a true 60/40 coin even though the coin came up 60 heads in 100 flips.

It’s like the AIDS test contradiction. If you are a healthy, heterosexual, non-drug user, and you take an AIDS test which has a 1% false positive rate and you test positive, you are extremely unlikely to have AIDS. There are very few people with AIDS in your population so it is much more likely that you do not have AIDS and got a false positive (1 in 100) than you did have AIDS in the first place (maybe 1 in 100,000) and tested positive. Out of a million people in your demographic, if they all got tested, 10 will have AIDS and test positive (assuming a 0% false negative rate) and 999,990 will not have AIDS, but 10,000 of them (1 in 100) will have a false positive. So the odds you have AIDS is 10,000 to 10 or 1000 to 1 against.

In the coin example where the spread of coin talent is small and most coins are still at or near 50/50, pretty much no matter what we get when flipping a coin 100 times, we are going to conclude that there is a good chance that our coin is still around 50/50 because most of the coins are around 50/50 in true coin talent. However, there is some chance that the coin is biased, if we get an unusual result.

Now, it is awkward and not particularly useful to conclude something like, “There is a 60% chance that our coin is a true 50/50 coin, 20% it is a 55/45 coin, etc.” So what we usually do is combine all those probabilities and come up with a single number called a weighted mean.

If one coin comes up 60/40, our weighted mean estimate of its “true talent” may be 52%. If we come up with 55/45, it might be 51%. 30/70 might be 46%. Etc. That weighed mean is what we refer to as “an estimate of true talent” and is the crucial factor in making decisions based on what we think the talent of the coins/players are likely to be in the present and in the future.

Now what if the spread of coin talent were still small, as in the above example, but we flipped the coins 500 times each? Say we came up with 60/40 again in 500 flips. The chances of that happening with a 60/40 coin is 24,000 times more likely than if the coin were 50/50! So now we are much more certain that we have a true 60/40 coin even if we don’t have that many of them in our bank. In fact, if the standard deviation of our spread in coin talent were 3%, we would be about ½ certain that our coin was a true 50/50 coin and half certain it was a true 60/40 coin, and our weighted mean would be 55%.

There is a much easier way to do it. We have to do some math gyrations which I won’t go into that will enable us to figure out how much to regress our observed flip percentage to the mean flip percentage of all the coins, 50%. For 100 flips it was a large regression such that with a 60/40 result we might estimate a true flip talent of 52%, assuming a spread of coin talent of 3%. For 500 flips, we would regress less towards 50% to give us around 55% as our estimate of coin talent. Regressing toward a mean rather than doing the long-hand Bayesian inferences using all the possible true talent states assumes a normal distribution or close to one.

The point is that the sample size of the observed measurement is determines how much we regress the observed amount towards the mean. The larger the sample, the less we regress. One season observed splits and we regress a lot. Career observed splits that are 5 times that amount, like our 500 versus 100 flips, we regress less.

But sample size of the observed results is not the only thing that determines how much to regress. Remember if all our coins were fair and there were no spread in talent, we would regress 100% no matter how many flips we did with each coin.

So what if there were a large spread in talent in the piggy bank? Maybe a SD of 10 percent so that almost all of our coins were anywhere from 20/80 to 80/20 (in a normal distribution the rule of thumb is that almost of the values fall within 3 SD of the mean in either direction)? Now what if we flipped a coin 100 times and came up with 60 heads. Now there are lots more coins at true 60/40 and even some coins at 70/30 and 80/20. The chances that we have a truly biased coin when we get an unusual result is much greater than if the spread in coin talent were smaller, even in 100 flips.

So now we have the second rule. The first rule was that the number of trials is important in determining how much credence to give to an unusual result, i.e., how much to regress that result towards the mean, assuming that there is some spread in true talent. If there is no spread, then no matter how many trials our result is based on, and no matter how unusual our result, we still regress 100% toward the mean.

All trials whether they be coins or human behavior have random results around a mean that we can usually model as long as the mean is not 0 or 1. That is an important concept, BTW. Put it in your “things I should know” book. No one can control or influence that random distribution. A human being might change his mean from time to time but he cannot change or influence the randomness around that mean. There will always be randomness, and I mean true randomness, around that mean regardless of what we are measuring, as long as the mean is between 0 and 1, and there is more than 1 trial (in one trial you either succeed or fail of course). There is nothing that anyone can do to influence that fluctuation around the mean. Nothing.

The second rule is that the spread of talent also matters in terms of how much to regress the actual results toward the mean. The more the spread, the less we regress the results for a given sample size. What is more important? That’s not really a specific enough question, but a good answer is that if the spread is small, no matter how many trials the results are based on, within reason, we regress a lot. If the spread is large, it doesn’t take a whole lot of trials, again, within reason, in order to trust the results more and not regress them a lot towards the mean.

Let’s get back to platoon splits, now that you know almost everything about sample size, spread of talent, regression to mean, and watermelons. We know that how much to trust and regress results depends on their sample size and on the spread of true talent in the population with respect to that metric, be it coin flipping or platoon splits. Keep in mind that when we say trust the results, that it is not a binary thing, as in, “With this sample and this spread of talent, I believe the results – the 60/40 coin flips or the 50 point reverse splits, and with this sample and spread, I don’t believe them.” That’s not the way it works. You never believe the results. Ever. Unless you have enough time on your hands to wait for an infinite number of results and the underlying talent never changes.

What we mean by trust is literally how much to regress the results toward a mean. If we don’t trust the stats much, we regress a lot. If we trust them a lot, we regress a little. But. We. Always. Regress. It is possible to come up with a scenario where you might regress almost 100% or 0%, but in practice most regressions are in the 20% to 80% range, depending on sample size and spread of talent. That is just a very rough rule of thumb.

We generally know the sample size of the results we are looking at. With Siegrest (I almost forgot what started this whole thing) his career TBF is 604 TBF, but that’s not his sample size for platoon splits because platoon splits are based on the difference between facing lefties and righties. The real sample size for platoon splits is the harmonic mean of TBF versus lefties and righties. If you don’t know what that means don’t worry about it. A shortcut is to use the lesser of the two which is almost always TBF versus lefties, or in Siegrest’s case, 231. That’s not a lot, obviously, but we have two possible things going for Maddon, who played his cards like Siegrest was a true reverse split lefty pitcher. One, maybe the spread of platoon skill among lefty pitchers is large (it’s not), and two, he has a really odd observed split of 47 points in reverse. That’s like flipping a coin 100 times and getting 70 heads and 30 tails or 65/35. It is an unusual result. The question is, again, not binary – whether we believe that -47 point split or not. It is how much to regress it toward the mean of +29 – the average left-handed platoon split for MLB pitchers.

While the unusual nature of the observed result is not a factor in how much regressing to do, it does obviously come into play, in terms of our final estimate of true talent. Remember that the sample size and spread of talent in the underlying population, in this case, all lefty pitchers, maybe all lefty relievers if we want to get even more specific, is the only thing that determines how much we trust the observed results, i.e., how much we regress them toward the mean. If we regress -47 points 50% toward the mean of +29 points, we get quite a different answer than if we regress, say, an observed -10 split 50% towards the mean. In the former case, we get a true talent estimate of -9 points and in the latter we get +10. That’s a big difference. Are we “trusting” the -47 more than the -10 because it is so big? You can call it whatever you want, but the regression is the same assuming the sample size and spread of talent is the same.

The “regression”, by the way, if you haven’t figured it out yet, is simply the amount, in percent, we move the observed toward the mean. -47 points is 76 points “away” from the mean of +29 (the average platoon split for a LHP). 50% regression means to move it half way, or 38 points. If you move -47 points 38 points toward +29 points, you get -9 points, our estimate of Siegrest’s true platoon split if  the correct regression is 50% given his 231 sample size and the spread of platoon talent among LH MLB pitchers. I’ll spoil the punch line. It is not even close to 50%. It’s a lot more.

How do we determine the spread of talent in a population, like platoon talent? That is actually easy but it requires some mathematical knowledge and understanding. Most of you will just have to trust me on this. There are two basic methods which are really the same thing and yield the same answer. One, we can take a sample of players, say 100 players who all had around the same number of opportunities (sample size), say, 300. That might be all full-time starting pitchers in one season and the 300 is the number of LHB faced. Or it might be all pitchers over several seasons who faced around 300 LHB. It doesn’t matter. Nor do the number of opportunities.  They don’t even have to be the same for all pitchers. It is just easier to explain that way. Now we compute the variance in that group – stats 101. Then we compare that variance with the variance expected by chance – still stats 101.

Let’s take BA, for example. If we have a bunch of players with 400 AB each, what is the variance in BA among the players expected by chance? Easy. Binomial theorem. .000625 in BA. What if we observe a variance of twice that, or .00125? Where is the extra variance coming from? A tiny bit is coming from the different contexts that the player plays in, home/road, park, weather, opposing pitchers, etc. A tiny bit comes from his own day-to-day changes in true talent. We’ll ignore that. They really are small. We can of course estimate that too and throw it into the equation. Anyway, that extra variance, the .000625, is coming from the spread of talent. The square root of that is .025 or 25 points of BA, which would be one SD of talent in this example. I just made up the numbers, but that is probably close to accurate.

Now that we know the spread in talent for BA, which we get from this formula – observed variance = random variance + talent variance – we can now calculate the exact regression amount for any sample of observed batting average or whatever metric we are looking at. It’s the ratio of random variance to total variance. Remember we need only 2 things and 2 things only to be able to estimate true talent with respect to any metric, like platoon splits: spread of talent and sample size of the observed results. That gives us the regression amount. From that we merely move the observed result toward the mean by that amount, like I did above with Siegrest’s -47 points and the mean of +29 for a league-average LHP.

The second way, which is actually more handy, is to run a regression of player results from one time period to another. We normally do year-to-year but it can be odd days to even, odd PA to even PA, etc. Or an intra-class correlation (ICC) which is essentially the same thing but it correlates every PA (or whatever the opportunity is) to every other PA within a sample.  When we do that, we either use the same sample size for every player, like we did in the first method, or we can use different sample sizes and then take the harmonic mean of all of them as our average sample size.

This second method yields a more intuitive and immediately useful answer, even though they both end up with the same result. This actually gives you the exact amount to regress for that sample size (the average of the group in your regression). In our BA example, if the average sample size of all the players were 500 and we got a year-to-year (or whatever time period) correlation of .4, that would mean that for BA, the correct amount of regression for a sample size of 500 is 60% (1 minus the correlation coefficient or “r”). So if a player bats .300 in 500 AB and the league average is .250 and we know nothing else about him, we estimate his true BA to be (.300 – .250) * .4 + .250 or .270. We move his observed BA 60% towards the mean of .250. We can easily with a little more math calculate the amount of regression for any sample size.

Using method #1 tells us precisely what the spread in talent is. Method 2 tells us that implicitly by looking at the correlation coefficient and the sample size. With either method, we get the amount to regress for any given sample size.

Platoon

Let’s look at some year-to-year correlations for a 500 “opportunity” (PA, BA, etc.) sample for some common metrics. Since we are using the same sample size for each, the correlation tells us the relative spreads in talent for each of these metrics. The higher the correlation for any given sample, the higher the spread in talent (there are other factors that slightly affect the correlation other than spread of talent for any given sample size but we can safely ignore them).

BA: .450

OBA: .515

SA: .525

Pitcher ERA: .240

BABIP for pitchers (DIPS): .155

BABIP for batters: .450

Now let’s look at platoon splits:

This is for an average of 200 TBF versus a LHP, so the sample size is smaller than the ones above.

Platoon wOBA differential for pitchers (200 BF v. LHB): .135

RHP: .110

LHP: .195

Platoon wOBA differential for batters (200 BF v. LHP): .180

RHB: .0625

LHB: .118

Those numbers are telling us that, like DIPS, the spread of talent among batters and pitchers with respect to platoon splits is very small. You all know now that this, along with sample size, tells us how much to regress an observed split like Siegrest’s -47 points. Yes, a reverse split of 47 points is a lot, but that has nothing to do with how much to regress it in order to estimate Siegrist’s true platoon split. The fact that -47 points is very far from the average left-handed pitcher’s +29 points means that it will take a lot of regression to moved it into the plus zone, but the -47 points in and of itself does not mean that we “trust it more.” If the regression were 99% then whether the observed were -47 or +10, we would arrive at nearly the same answer. Don’t confuse the regression with the observed result. One has nothing to do with the other. And don’t think in terms of “trusting” the observed result or not. Regress the result and that’s your answer. If you arrive at answer X it makes no difference whether your starting point, the observed result, was B, or C. None whatsoever.  That is a very important point. I don’t know how many times I have heard, “But he had a 47 point reverse split in his entire career!” You can’t possibly be saying that you estimate his real split to be +10 or +12 or whatever it is.” Yes, that’s exactly what I’m saying. A +10 estimated split is exactly the same whether the observed split were -47 or +5. The estimate using the regression amount is the only thing that counts.

What about the certainty of the result? The certainty of the estimate depends mostly on the sample size of the observed results. If we never saw a player hit before and we estimate that he is a .250 hitter we are surely less certain than if we have a hitter who has hit .250 over 5000 AB. But does that change the estimate? No. The certainty due to the sample size was already included in the estimate. The higher the certainty the less we regressed the observed results. So once we have the estimate we don’t revise that again because of the uncertainty. We already included that in the estimate!

And what about the practical importance of the certainty in terms of using that estimate to make decisions? Does it matter whether we are 100% or 90% sure that Siegrest is a +10 true platoon split pitcher? Or whether we are only 20% sure – he might actually have a higher platoon split or a lower one? Remember the +10 is a weighted mean which means that it is in the middle of our error bars. The answer to that is, “No, no and no!” Every decision that a manager makes on the field is or should be based on weighted mean estimates of various player talents. The certainty or distribution rarely should come into play. Basically the noise in the result of a sample of 1 is so large that it doesn’t matter at all what the uncertainty level of your estimates are.

So what do we estimate Siegrest’s true platoon split, given a 47 point reverse split in 231 TBF versus LHB. Using no weighting for more recent results, we regress his observed splits 1 minus 230/1255, or .82 (82%) towards the league average for lefty pitchers, which is around 29 points for a LHP. 82% of 76 points is 62 points. So we regress his -47 points 62 points in the plus direction which gives us an estimate of +15 points in true platoon split. That is half the split of an average LHP, but it is plus nonetheless.

That means that a left-handed hitter like Coghlan will hit better than he normally does against a left-handed pitcher. However, Coghlan has a larger than average estimated split, so that cancels out Siegrest’s smaller than average split to some extent. That also means that Soler or another righty will not hit as well against Siegrest as he would against a LH pitcher with average splits. And since Soler himself has a slightly smaller platoon split than the average RHB, his edge against Siegrest is small.

We also have another method for better estimating true platoon splits for pitchers which can be used to enhance the method we use using sample results, sample size, and means. It is very valuable. We have a pretty good idea as to what causes one pitcher to have a smaller or greater platoon split than another. It’s not like pitchers deliberately throw better or harder to one side or the other or that RH or LH batters scare or distract them. Pitcher platoon splits mostly come from two things: One is arm angle. If you’ve ever played or watched baseball that should be obvious to you. The more a pitcher comes from the side, the tougher he is on same-side batters and the larger his platoon split. That is probably the number one factor in these splits. It is almost impossible for a side-armer not to have large splits.

What about Siegrest? His arm angle is estimated by Jared Cross of Steamer, using pitch f/x data, at 48 degrees. That is about a ¾ arm angle. That strongly suggests that he does not have true reverse splits and it certainly enables us to be more confident that he is plus in the platoon split department.

The other thing that informs us very well about likely splits is pitch repertoire. Each pitch has its own platoon profile. For example, pitches with the largest splits are sliders and sinkers and those with the lowest or even reverse are the curve (this surprises most people), splitter, and change.

In fact, Jared (Steamer) has come up with a very good regression formula which estimates platoon split from pitch repertoire and arm angle only. This formula can be used by itself for estimating true platoon splits. Or it can be used to establish the mean towards which the actual splits should be regressed. If you use the latter method the regression percentage is much higher than if you don’t. It’s like adding a lot more 50/50 coins to that piggy bank.

If we plug Siegrest’s 2015 numbers into that regression equation, we get an estimated platoon from arm angle and pitch repertoire of 14 points, which is less than the average lefty even with the 48 degree arm angle. That is mostly because he uses around 18% change ups this year. Prior to this season, when he didn’t use the change up that often, we would probably have estimated a much higher true split.

So now rather than regressing towards just an average lefty with a 29 point platoon split, we can regress his -47 points to a more accurate mean of 14 points. But, the more you isolate your population mean, the more you have to regress for any given sample size, because you are reducing the spread of talent in that more specific population. So rather than 82%, we have to regress something line 92%. That brings -47 to +9 points.

So now we are down to a left-handed pitcher with an even smaller platoon split. That probably makes Maddon’s decision somewhat of a toss-up.

His big mistake in that same game was not pinch-hitting for Lester and Ross in the 6^th. That was indefensible in my opinion. Maybe he didn’t want to piss off Lester, his teammates, and possibly the fan base.Who knows?

And you think that was bad?

Last night I lambasted the Cardinals’ sophomore manager, Mike Matheny, for some errors in bullpen management that I estimated cost his team over 2% in win expectancy (WE). Well, after tonight’s game, all I have to say is, as BTO so eloquently said, “You ain’t seen nothin’ yet!”

Tonight (or last night, or whatever), John Farrell, the equally clueless manager of the Red Sox (God, I hope I don’t ever have to meet these people I call idiots and morons!), basically told Matheny, “I’ll see your stupid bullpen management and raise you one moronic non-pinch hit appearance!”

I’m talking of course about the top of the 7th inning in Game 5. The Red Sox had runners on second and third, one out, and John Lester, the Sox’ starter was due to hit (some day, I’ll be telling my grandkids, “Yes, Johnny, pitchers once were also hitters.”). Lester was pitching well (assuming you define “well” as how many hits/runs he allowed so far – not that I am suggesting that he wasn’t  pitching “well”) and had only thrown 69 pitches, I think. I don”t think it ever crossed Farrell’s mind to pinch hit for him in that spot. The Sox were also winning 2-1 at the time, so, you know, they didn’t need any more runs in order to guarantee a win <sarcasm>.

Anyway, I’m not going to engage in a lot of hyperbole and rhetoric (yeah, I probably will). It doesn’t take a genius to figure out that not pinch hitting for Lester in that particular spot (runners on 2nd and 3rd, and one out) is going to cost a decent number of fraction of runs. It doesn’t even take a genius, I don’t think, to figure out that that means that it also costs the Red Sox some chance of ultimately winning the game. I’ll explain it like I would to a 6-year-old child. With a pinch hitter, especially Napoli, you are much more likely to score, and if you do, you are likely to score more runs. And if on the average you score more runs that inning with a pinch hitter, you are more likely to win the game, since you only have a 1 run lead and the other team still gets to come to bat 3 more times. Surely, Farrell can figure that part out.

How many runs and how much win expectancy does that cost, on the average? That is pretty easy to figure out. I’ll get to that in a second (spoiler alert: it’s a lot). So that’s the downside. What is the upside? It is two-fold, sort of. One, you get to continue to pitch Lester for another inning or two. I assume that Farrell does not know exactly how much longer he plans on using Lester, but he probably has some idea. Two, you get to rest your bullpen in the 7th and possibly the 8th.

Both of those upsides are questionable in my opinion, but, as you’ll see, I will actually give Farrell and any other naysayer (to my way of thinking) the benefit of the doubt. The reason I think it is questionable is this: Lester, despite pitching well so far, and only throwing 69 pitches, is facing the order for the 3rd time in the 7th inning, which means that he is likely .4 runs per 9 innings worse than he is overall, and the Red Sox, like most World Series teams, have several very good options in the pen who are actually at least as good as Lester when facing the order for the third time, not to mention the fact that Farrell can mix and match his relievers in those two innings on order to get the platoon advantage. So, in my opinion, the first upside for leaving in Lester is not an upside at all.  But, when I do my final analysis, I will sort of assume that it is, as you will see.

The second upside is the idea of saving the bullpen, or more specifically, saving the back end of the bullpen, the short relievers. In my opinion, again, that is a sketchy argument. We are talking about the Word Series, where you carry 11 or 12 pitchers in order to play 7 games in 9 days and then take 5 months off. In fact, tomorrow (today?) is an off day followed by 2 more games and then they all go home. Plus, it’s not like either bullpen has been overworked in the post-season so far. But, I will be happy to concede that “saving your pen” is indeed an upside for leaving Lester in the game. How much is it worth? No one knows, but I don’t think anyone would disagree with this: A manager would not choose to “save” his bullpen for 1-2 innings when there is an off day followed by 2 more games, followed by 100 off days, when the cost of that savings is a significant chunk of win expectancy in the game he is playing at the present time. I mean, if you don’t agree with that, just stop reading and don’t ever come back to this site.

The final question, then, is how much in run or win expectancy did that non-pinch hit cost? Remember in my last post how I talked about “categories” of mistakes that a manager can make? I said that a Category I mistake, a big one, cost a team 1-2% in win expectancy. That may not seem like a lot for one game, but it is. We all criticize managers for “costing” their team the game when we think  they made a mistake and their team loses. If you’ve never done that, then you can stop reading too. The fact of the matter is that there is almost nothing a manager can do, short of losing his mind and pinch hitting the bat boy in a high leverage situation, that is worth more than 1 or 2% in win expectancy. Other than this.

The run expectancy with runners on second and third and one out in a low run environment is around 1.40. That means that on the average with a roughly average hitter at the plate, the batting team will score, on the average, 1.40 runs during that inning, from that point on. We’ll assume that it is about the same if Napoli pinch hit. He is a very good pinch hitter, but there is a pinch hitting penalty and he is facing a right handed pitcher. To be honest, it doesn’t really matter. It could be 1.2 runs or 1.5 runs. It won’t make much of a difference.

What is the run expectancy with Lester at the plate? I don’t know much about his hitting, but I assume that since he has never been in the NL, and therefore hardly ever hits, it is not good. We can easily say that it is below that of an average pitcher, but that doesn’t really matter either. With an average pitcher batting in that same situation, and the top of the order coming up, the average RE is around 1.10 runs. So the difference is .3 runs. Again, it doesn’t matter much if it is .25 or .4 runs. And there really isn’t much wiggle room. We know that it is a run scoring situation and we know that a pinch hitter like Napoli (or almost anyone for that matter) is going to be a much better hitter than Lester. So .3 runs sounds more than reasonable. Basically we are saying that, on the average, with a pinch hitter like Napoli at the plate in that situation, runners on 2nd and 3rd with 1 out, the Red Sox will score .3 more runs than with Lester at the plate. I don’t know that anyone would quarrel with that – even someone like a Tim McCarver or Joe Morgan.

In order to figure out how much in win expectancy that is going to cost, again, on the average, first we need to multiply that number by the leverage index in that situation. The LI is 1.64.  1.64 times .3 runs divided by 10 is .049 or 4.9%. That is the difference in WE between batting Lester or a pinch hitter. It means that with the pinch hitter, the Red Sox can expect, on the average, to win the game around 5% more often than if Lester hits, everything else being equal. I don’t know whether you can appreciate the enormity of that number. I have been working with these kinds of numbers for over 20 years. If you can’t appreciate it, you will just have to take my word for it that that is a ginormous number when it comes to WE in one game. As I said, I usually consider an egregious error to be worth 1-2%. This is worth almost 5%. That is ridiculous. It’s like someone offering you a brand new Chevy or Mercedes for the same price. And you take the Chevy, if you are John Farrell.

Just to see if we are in the right ballpark with our calculations, I am going to to run this scenario through my baseball simulator, which is pretty darn accurate (even though it does not have an algorithm for heart or grit) in these kinds of relatively easy situations to analyze.

Sound of computers whirring….

With Lester hitting, the Red Sox win the game 76.6% of the time. And therein lies the problem! Farrell knows that no matter what he does, he is probably going to win the game, and if he takes out Lester, not only is he going to bruise his feelings (boo hoo), but if the relief core blows the game, he is going to be lambasted and probably feel like crap. If he takes Lester out, he knows he’s also going to probably win the game, and what’s a few percent here and there. But if he lets Lester continue, as all of Red Sox nation assumes and hopes he will, and then they blow the game, no one is going to blame Farrell. You know why? Because at the first sign of trouble, he is going to pull Lester, and no one is going to criticize a manager for leaving in a pitcher who is pitching a 3-hitter through 6 innings and only 69 pitches and yanks him as soon as he gives up a baserunner or two. So letting Lester hit for himself is the safe decision. Not a good one, but a safe one.

After that rant, you probably want to know how often the Sox win if they pinch hit for Lester. 79.5% of the time. So that’s only a 2.9% difference. Still higher than my formerly highest Category of manager mistakes, 1-2%.

Let’s be conservative and call it a 3% mistake. I wonder if you told John Farrell that by not pinch hitting for Jon Lester his team’s chances of winning go from 79.5% to 76.6%. Even if he believed that, do you think it would sway his decision? I don’t think so, because he feels with all his heart and soul that having Lester, who is “dealing,” pitch another inning or two, and saving his bullpen, is well worth the difference between 77% and 80%. After all, either way, they probably win.

So how much does Lester pitching another inning or two (we’ll call it 1.5 innings, since at the time it could have been anywhere from 0 to 2, I think  – I am pretty sure that Koji was pitching the 9th no matter what) gain over another pitcher? Well, I already said that the answer is nothing. Any of their good relievers are at least as good as Lester the 3rd time though the order. But I also said that I will concede that Lester is going to be just amazing, on the average, if Farrell leaves him in the game. How good does he have to be in order to make up the .3 runs or 3% in WE that are lost by allowing Lester to hit?

A league average reliever allows around 4 runs a game. It doesn’t matter what that exact number is – we are only using it for comparison purposes. A good short reliever actually allows more like 3 or 3.5 runs a game. Starting pitchers, in general, are a little worse than the average pitcher (because of that nasty times through the order penalty). A very good pitcher like Lester allows around 3.5 runs a game (a pitcher like Wainwright around 3 runs a game). So let’s assume that a very average reliever came into the game to pitch the 7th and half the 8th rather than Lester. They would allow 4 runs a game. That is very pedestrian for a reliever. Almost any short reliever can do that with his eyes closed. In order to make up the .3 runs we lost by letting Lester hit, Lester needs to allow fewer runs than 4 runs a game. How much less? Well, .3 runs in 1.5 innings is .2 runs per inning. .2 runs per inning times 9 innings is 1.8 runs. So Lester would have to pitch like a pitcher who allows 2.2 runs per 9 innings. No starting pitcher like that exists. Even the best starter in baseball, Clayton Kershaw, is a 2.5 run per 9 pitcher at best.

Let’s go another route. Remember that I said Lester was probably around a 3.5 run pitcher (Steamer, a very good projection system, has him projected with a 3.60 FIP, which is around a 3.5 pitcher in my projection system), but that the third time through the order he is probably a 3.80 or 3.90 pitcher. Forget about that. Let’s decree that Lester is indeed going to pitch the 7th and 8th innings, or however long he continues, like an ace reliever. Let’s call him a 3.00 pitcher, not the 3.80 or 3.90 pitcher that I think he really is, going into the 7th inning.

In case, you are wondering, there is no evidence that good or even great pitching through 6 or 7 innings predicts good pitching for future innings. Quite the contrary. Even starters who are pitching well have the times through the order penalty, and if they are allowed to continue, they end up pitching worse than they do overall in a random game. That is what real life says. That is what happens. It is not my opinion, observation, or recollection. A wise person once said that, “Truth comes from evidence and not opinion or faith.”

But, again, we are living on Planet Farrell, so we are conceding that Lester is a great pitcher going into the 7th inning and the third time through the order. (Please don’t tell me how he did that inning. If you do or even think that, you need to leave and never come back. Seriously.)  We are calling him a 3.0 pitcher, around the same as a very good closer.

How bad does a replacement for Lester for 1.5 innings have to be to make up for that .3 runs? Again, we need .2 runs per inning, times 9 innings, or a total of 1.8 runs per 9. So the reliever to replace him would have to be a 4.8 pitcher. That is a replacement pitcher folks, There is no one on either roster who is even close to that.

So there you have it. Like Keith Olbermann’s, Worst person in the world, we have the worst manager in baseball – John Farrell.

Addendum: Please keep in mind that some of the hyperbole and rhetoric is just that. Take comments like, “Farrell is an idiot,” or, “the worst manager in baseball,” with a grain of salt and chalk it up to flowery emotion. It is not relevant to the argument of course. The argument speaks for itself, and you, the reader, are free to conclude what you want about whether his moves, or any other managerial moves that I might discuss, were warranted or not.

I am not insensitive to factors that drive all managers’ decisions, like the reaction, desires, and opinions of the fans, media, upper management, and especially, the players. As several people have pointed out, if a manager were to do things that were “technically” correct, yet in doing so, alienate his players (and/or the fans) thereby affecting morale, loyalty, and perhaps a conscious or subconscious desire to win, then those “correct” decisions may become “incorrect” in the grand scheme of things.

That being said, my intention is to inform the reader and to take the hypothetical perspective of informing the manager of the relevant and correct variables and inputs such that they and you can make an informed decision. Imagine this scenario: I am sitting down with Farrell and perhaps the Red Sox front office and we are rationally and intelligently discussing ways to improve managerial strategy. Surely no manager can be so arrogant as to think that everything he does is correct. You would not want an employee like that working for your company no matter how much you respect him and trust his skills. Anyway, let’s say that we are discussing this very same situation, and Farrell says something like, “You know, I really didn’t care whether I removed Lester for a pinch hitter or not, and I don’t think he or my players would either. Plus, the preservation of my bullpen was really a secondary issue. I could have easily used Morales, Dempster, or even Breslow again. Managers have to make tough decisions like that all the time. I genuinely thought that with Lester pitching and us already being up a run, we had the best chance to win. But now that you have educated me on the numbers, I realize that that assumption on my part was wrong. In the future I will have to rethink my position if that or a similar situation should come up.”

That may not be a realistic scenario, but that is the kind of discussion and thinking I am trying to foster.

MGL