On the list of things I thought I’d be writing about today, Andy Sonnanstine ranked somewhere just south of nuclear physics. He was among the worst pitchers in baseball last year, running a 7.09 FIP in 36 innings at the big league level, leading the Rays to non-tender him yesterday and put his Major League career in jeopardy. He’ll probably be able to land a minor league deal from some team that needs Triple-A innings, but there’s a pretty decent chance that he’s seen his last days in the big leagues.
So, why am I writing about him? Well, thanks to the rabbit hole that David Appelman has created with his custom reports features on the leaderboards (seriously, if you’re not using these, you’re really missing out), I ended up spending a decent amount of time this morning looking at some of the differences in how pitchers perform in various situations. What led me down this path?
Well, when looking at Sonnanstine’s player card, I noticed that his career LOB% was an incredibly low 65.5%, the kind of number that is almost always driven by a relatively terrible performance with men on base. Some pitchers just do not perform well pitching from the stretch, so the gap between their bases empty performance and their men-on-base performance can be stark. Indeed, when looking at Sonnanstine’s splits, this is exactly what we find.
With the bases empty, opposing batters have hit him for just a .257/.301/.439 mark, but with men on base, the slash line jumps to .329/.375/.528, thanks mainly to a dramatic spike in the BABIP he allows. It’s hard to keep runners from scoring when you give up a .900 OPS to opposing batters when there are runners to drive in, and so Sonnanstine’s results have been a lot worse than looking at his numbers in a context-neutral environment would suggest. Given that he’s a guy with extremely fringey stuff anyway, it’s not hard to believe that Sonnanstine just loses enough velocity and movement without the benefit of the wind-up that he turns into a pumpkin in those situations, but I felt like we needed a baseline to compare his situational splits to.
So, I pulled up the league averages for performances with the bases empty, men on base, and runners in scoring position. Here are the relevant numbers over the last 10 years (note that BB% here excludes intentional walks):
Walk rate is lowest with men on base, then goes up as the situation gets more threatening. This makes intuitive sense, as pitchers are far more willing to pound the zone and risk the chance of a home run if it will only cost them one run. Once you put them in a situation where a hit could drive in runs, they begin to nibble, and thus, walk rate goes up.
Strikeout rate is highest with the bases empty, which goes along with pitchers pounding the zone when the cost for doing so is lowest. We’ll see the fruits of that trade-off in the next table.
And here’s the cost of throwing all those strikes with the bases empty – home run rate is dramatically higher when there’s no one on base, even though pitching from the wind-up is theoretically an advantage for the pitcher. Pitchers are clearly okay giving up an occasional solo home run to keep out of rally situations.
And now, the interesting table, and the one that relates most to Sonnanstine.
As you can see, BABIP is essentially even with the bases empty and with men on base, and then actually goes down with runners in scoring position, which is not what I expected to see. Given that the bases empty situation is almost always is a from-the-wind-up pitch, that the defense gets to align itself optimally with no runner on first to hold, and that selection bias means that a greater proportion of the sample pitched by high quality pitchers, I would have expected BABIP to be lowest with no one on.
Instead, we see the opposite, as it is historically and consistently lower in the highest leverage situations. My guess is that this has to do with more relief pitchers (who run lower than average BABIPs as a group) pitching in RISP situations and potentially a selection bias effect on the hitters due to intentional walks, but those are just untested theories at the moment. Still, regardless of the reason, the data doesn’t lie – there is no league-wide evidence that pitcher BABIP rises significantly when a man reaches base.
Theoretically, a pitcher who posts tremendously different BABIPs in the various baserunner situations is likely due for some regression. That isn’t to say that there is no variance in ability to pitch out of the stretch and that every pitcher is going to perform at league averages in those situations, but it does offer some hope for pitchers like Sonnanstine – his abysmal performances with men on base might not be quite as predictive as just looking at his slash line suggests. You may not look at Sonnastine’s career .306 BABIP and see much room for him to improve, but the timing of when he’s given up those hits may not say too terribly much about when he’s going to give up hits going forward. Simply redistributing some of his hits on balls in play from men on base to bases empty situations could have a pretty significant effect on his results, and make him a potentially decent back-of-the-rotation guy for a team that plays in a big park.
By the way, here are 20 pitchers whose BABIP splits diverged greatly last year. If you’re looking for a list of candidates whose 2012 results might be quite a bit different than their 2011 results, this is a pretty good place to start.