Fangraphs interview Capo David Laurila had a nice review of a presentation by Dan Rosenheck at the recent Sloan Sports Analytics Conference hosted by MIT. BABIP is something that can be incredibly useful for framing how a batter has fared on balls in play. It’s main flaw is that, as currently constructed, it is impossible to parse out whether deviations from the norm are due to random chance, “luck,” or if it’s due to quality of contact. Either nugget would give us useful information, but we cannot determine which fork we’re taking when we see a batter/pitcher with an abnormally high/low BABIP.
Dan’s research is quite interesting, if not intuitive. The higher the frequency of a batted ball trajectory turning into an out the lower a BABIP will be. If a batter has a preponderance to pop the ball up on the infield then it should not be a surprise that the batter has a low BABIP. Likewise, a pitcher that misses bats within the zone is doing something right. That pitcher is crushing batters with stuff and/or deception, such that, batters are not regularly making solid contact. Softly hit balls rarely go for base hits even if you’ll see this happen with a duck snort, flair, seeing eye single, or an infield base hit once or twice almost every game.
Well, Dan did the legwork and we all look forward to seeing the equation he derived from this which showed such promising results. Being able to explain why some pitchers can consistently be better/worse than league average is an exciting thing. The Rays own Jeremy Hellickson is probably the biggest reason this author finds this exciting. Year after year pundits describe that Jeremy Hellickson is going to fall of a cliff due to the vast chasm between his ERA and FIP. And the last two years Hellickson has gone out and defied the critics. Interestingly, FIP does not include either pop ups nor zone contact rates, the two things that Dan most heavily addressed in his study. Even more interesting is how well Hellickson has been at inducing pop ups and missing bats within the zone.
From 2010 to 2012 Hellickson has compiled a BABIP of .240. All batters in the league hit like a Ray when facing Jeremy Hellickson. Meanwhile, league average sits at .291 for the 127 qualified starting pitchers over this time frame. We can use an ad hoc statistic called BABIP+ to say that Hellickson has been 21% better than league average over this period (.291/.240 = 1.21). This is the best of this sample. We can use this same population and similarly manipulate his Zone Contact and IFFB rates and come up with figures of 1.05 and 1.39, respectively. Hellickson has had the 8th best Zone Contact rate at 84.6% over the last three years while league average has been 88.4%. Likewise, he’s had the 7th best IFFB% at 13.4% compared to a league average of 9.6%.
BABIP, Zone Contact, and IFFB% are all subject to variation and it’s quite likely that some favorable luck has already pushed Hellickson further out from the norm, but studies like this should be lending more credibility to what Hellickson has done thus far, while leaving more room for optimism going forward. Yes, Jeremy Hellickson receives some BABIP suppression playing in front of a good defense in a stadium that punishes batters, but he also has shown a couple of things that can and should be considered skills that also allow him to churn outs out of balls in play in the past and going forward. We say this every year, but it will be fun to monitor how these things hold up this season.