On the surface, it would appear as Jeremy Hellickson has improved since his 2010 debut. After all, his 3.21 ERA is lower than his 3.47 ERA from a season ago in a sample selection that is three times the size. Meanwhile, his strikeouts have dropped, his walks increased, and home runs have remained largely static.
The biggest reason for Hellickson’s improved ERA is a .224 batting average on balls in play (BABIP). The Rays’ staff as a whole has a lower than normal BABIP, but Hellickson is about .30 points ahead of everyone else in the rotation. Given the average defensive independent metrics and the low BABIP once could easily come to the conclusion that Hellickson’s success thus far is largely based on luck.
Lady luck may very well be on Hellickson’s side, but there could also be another explanation; especially for the BABIP. Of pitchers with at least 100 innings pitched this season, Jeremy Hellickson has the fourth highest infield flyball (IFFB) rate. Infield flyballs are almost always converted in to outs (around 98% of the time) and if a runner is on base, they are not likely to advance. With a 15.5% IFFB rate, a large chunk of the balls put in play against Hellickson are falling into his fielder’s gloves like the proverbial can of corn off the shelf.
According to work done by Derek Carty – now of Baseball Prospectus – IFFB rate stabilizes around the halfway point of the season for most pitchers. Hellickson is roughly just passed the halfway point with 16 starts and 103.2 innings pitched. If Carty’s findings are true, then Hellickson’s high rate of infield flyballs are not a fluke and appear to be a repeatable skill.
If this is the case, Hellickson may organically outperform his defensive independent metrics and keep a lower than normal BABIP without much “luck” involved. Also consider that despite the lower strikeout rate, Hellickson is still getting nearly 11% swinging strikes. Perhaps some better sequencing would increase the strikeouts. That said, if he continues to get infield flies 15% of the time, he may not need to.