Rich Hill Pretty Much Abandoned His Fastball

I don’t think I’m telling tales outside of school to say that Rich Hill throws his curveball a lot. In 2016, for example, he threw it literally half the time. With good reason too: amongst major league starters who threw at least 100 innings, it ranked 3rd in Pitch/FX’s pitch value metric behind the late great Jose Fernandez and the just great Corey Kluber. By shirking tradition and using the curve as his primary pitch, Hill managed elite numbers through his injury-shortened season: 10.5 k/9 and just 2.7 bb/9 supporting a 2.12 ERA (backed up by a 2.39 FIP). He may have gotten a little bit lucky with just a 0.33 HR/9 allowed, but there’s no denying that curveball is tough to square up.

This leads to the central reason for writing this post. Rich Hill made his season debut last night with the Dodgers and while watching the game I thought that he was throwing a lot of curveballs, even for him. Here’s a second inning at bat against rookie Hunter Renfroe, in which the black dot represents fastballs and the yellow dots represent curveballs:

Here’s that same at bat shown in a more eye-pleasing manner, courtesy of the MLB At Bat app:

The first pitch, which is shown sans classification, was a fastball. Hill missed with a fastball, and then missed with a curveball. Then, he proceeded to throw five more curveballs in a row. I think we can all agree that’s a lot of curveballs. While he didn’t quite keep that ratio up all game, he did end up spinning 47 curves out of his 75 total pitches, or, if you prefer, about 63%.

While it’s obviously only 5 innings of work, I’m definitely curious to see if Hill will keep up this new even more extreme usage of the curveball. Context counts for a lot in baseball, and pitch sequencing can be just as important to the outcome of an at bat as the pitches themselves. It seems to me that Hill, like the raptors in Jurassic Park systematically testing the fences for weaknesses, is trying to see how often he can throw the bender and still befuddle batters with it. Maybe it’s just damn near unhittable, even when they know that it’s coming. It should be said that in Renfroe’s next at bat, he saw a fastball followed by four straight curves. The last of those was hit over the fence. Still, that was one of only two hits surrendered on the evening, so the early results are very promising.