Yesterday, I posted an article describing how I modeled to some extent a way to tell whether and by how much pitchers may be able to pitch in such a way as to allow fewer or more runs than their components, including the more subtle ones, like balks, SB/CS, WP, catcher PB, GIDP, and ROE suggest.
For various reasons, I suggest taking these numbers with a grain of salt. For one thing, I need to tweak my RA9 simulator to take into consideration a few more of these subtle components. For another, there may be some things that stick with a pitcher from year to year that have nothing to do with his “RA9 skill” but which serve to increase or decrease run scoring, given the same set of components. Two of these are a pitcher’s outfielder arms and the vagueries of his home park, which both have an effect on base runner advances on hits and outs. Using a pitcher’s actual sac flies against will mitigate this, but the sim is also using league averages for base runner advances on hits, which, as I said, can vary from pitchers to pitcher, and tend to persist from year to year (if a pitcher stays on the same team) based on his outfielders and his home park. Like DIPS, it would be better to do these correlations only on pitchers who switch teams, but I fear that the sample would be too small to get any meaningful results.
Anyway, I have a database now of the last 10 years’ differences between a pitcher’s RA9 and his sim RA9 (the runs per 27 outs generated by my sim), for all pitchers who threw to at least 100 batters in a season.
First here are some interesting categorical observations:
Jared Cross, of Steamer projections, suggested to me that perhaps some pitchers, like lefties, might hold base runners on first base better than others, and therefore depress scoring a little as compared to the sim, which uses league-average base running advancement numbers. Well, lefties actually did a hair worse in my database. Their RA9 was .02 greater than their sim RA. Righties were -.01 better. That does not necessarily mean that RHP have some kind of RA skill that LHP do not have. It is more likely a bias in the sim that I am not correcting for.
How about number of pitches in a pitcher’s repertoire. I hypothesized that pitchers with more pitches would be better able to tailor their approach to the situation. For example, with a base open, you want your pitcher to be able to throw lots of good off-speed pitches in order to induce a strikeout or weak contact, whereas you don’t mind if he walks the batter.
I was wrong. Pitchers with 3 or more pitches that they throw at least 10% of the time are .01 runs worse in RA9. Pitchers with only 2 or fewer pitches, are .02 runs better. I have no idea why that is.
How about pitchers who are just flat out good in their components such that their sim RA is low, like under 4.00 runs? Their RA9 is .04 worse. Again, their might be some bias in the sim which is causing that. Or perhaps if you just go out and there “air it out” and try and get as many outs and strikeouts as possible, regardless of the situation, you are not pitching optimally.
Conversely, pitchers with a sim RA of 4.5 or greater shave .03 points off their RA9. If you are over 5 in your sim RA, your actual RA9 is .07 points better and if you are below 3.5, your RA9 is .07 runs higher. So, there probably is something about having extreme components that even the sim is not picking up. I’m not sure what that could be. Or, perhaps if you are simply not that good of a pitcher, you have to find ways to minimize run scoring above and beyond the hits and walks you allow overall.
For the NL pitchers, their RA9 is .05 runs better than their sim RA, and for the AL, they are .05 runs worse. So the sim is not doing a good job with respect to the leagues, likely because of pitchers batting. I’m not sure why, but I need to fix that. For now, I’ll adjust a pitcher’s sim RA according to his league.
You might think that younger pitchers would be “throwers” and older ones would be “pitchers” and thus their RA skill would reflect that. This time you would be right – to some extent.
Pitchers less than 26 years old were .01 runs worse in RA9. Pitchers older than 30 were .03 better. But that might just reflect the fact that pitchers older than 30 are just not very good – remember, we have a bias in terms of quality of the sim RA and the difference between that and regular RA9.
Actually, even when I control for the quality of the pitcher, the older pitchers had more RA skill than the younger ones by around .02 to .04 runs. As you can see, none of these effects, even if they are other than noise, is very large.
Finally, here are the lists of the 10 best and worst pitchers with respect to “RA skill,” with no commentary. I adjusted for the “quality of the sim RA” bias, as well as the league bias. Again, take these with a large grain of salt, considering the discussion above.
Sean Chacon -.18
Steve Trachsel -.18
Francisco Rodriguez -.18
Jose Mijares -.17
Scott Linebrink -.16
Roy Oswalt -.16
Dennys Reyes -.15
Dave Riske -.15
Ian Snell -.15
5 others tied for 10th.
Derek Lowe .27
Luke Hochevar .20
Randy Johnson .19
Jeremy Bonderman .18
Blaine Boyer .18
Rich Hill .18
Jason Johnson .18
5 others tied for 8th place.
(None of these pitchers stand out to me one way or another. The “good” ones are not any you would expect, I don’t think.)