How Jeremy Hellickson Gets His Popups

Jeremy Hellickson is a flyball pitcher. This season he allowed flies on 46.4% of all balls put in play. Normally I would consider this a warning sign, as while groundballs tend to become outs (sometimes double plays) or singles, flyballs also go for doubles, triples, and home runs, and only very rarely turn into double plays. However, as Tommy Rancel pointed out in his Rays Insider piece on 1040 ESPN Tampa Bay, Jeremy Hellickson gets a lot of infield flyballs. Infield flyballs almost always become outs, and what's more, there's some evidence that inducing high infield flyball rates is a repeatable skill, most often shown by extreme flyball pitchers, like Hellickson. Hellickson's infield flyball rate (IFFB%) for this season is 14.2%, meaning that 30.0% of his flyballs have been popups. (Note: My numbers come courtesy of Joe Lefkowitz. They're slightly different than Fangraphs, which I think is what Tommy Rancel used. I'm really not sure why.)

It's of course far too early in his career to say for sure if Hellickson is just getting lucky, or if he does in fact have a special skill for generating popups, but I think it's worth taking a close look at how he's getting them.

Hellickson has induced infield flyballs at a much higher rate from left handed hitters than he has from right handed hitters. Lefties have hit 44 infield flies and 74 outfield flies compared with 20 infield flies and 72 outfield flies to righties. Much of this discrepancy comes from the changeup, which Hellickson throws to hitters of either handedness, but which got him 14 popups against lefties but only two against righties. Here's a complete breakdown of Hellickson's flyballs by pitch type. Note that the relatively small percentage on the changeup are due to it's lack of effectiveness in inducing popups to right handed batters.

In terms of location, height does seem to matter. The average height in the strike zone of one of Hellickson's infield popups was 2.7 inches higher than that of his outfield flies. Also, fastballs inside created more popups than outside fastballs. I find this interesting, as it seems to suggest that Helly is successful by pretending he's a power pitcher and busting players up and in with his modest fastball. It makes me wonder if it's not so much that velocity allows a pitcher to succeed up and in, but rather that velocity gives a pitcher the confidence to live up and in to batters, where he can succeed.

I've created a Tableau worksheet for you to play around in. You can control what data is being shown by changing which boxes are checked. Go ahead and post any interesting patterns you uncover.