Data from Tyler Chatwoood’s first start suggests he’s been working on some mechanical tweaks. Specifically, his horizontal and vertical release points look very different from previous seasons.
Much has been made about Chatwood’s top-tier spin rate, even before the inked up the former Rockies starter to a unique deal this past winter. And while it’s true that the righty has some of the most impressive spin in MLB, I found that Chatwood’s pitch RPM’s don’t correlate to whiffs or run prevention.
Perhaps his spin rate doesn’t translate to optimal movement because he throws from more of a three-quarters slot rather than coming over the top. As Eno Sarris pointed out in FanGraphs immediately after the Cubs signed Chatwood, the pitcher might better capitalize on that spin rate by reverting back to his pre-2016 days when he was throwing more over the top.
Though it’s still very early, data from Chatwood’s first start shows that he is indeed doing just that. Look first at the horizontal movement graph below. The 2018 data points are higher, meaning he’s letting go of pitches closer to his body and less towards the third-base side. There is not a statistically significant difference in release points for his curveball, but there were some curves that were released closer to his body. Over time, perhaps this will continue to trend more in line with his other pitches.
Chatwood’s vertical release point, on the other hand — that’s a figure of speech, of course, since he’s still throwing with his right hand — is actually lower. The curve is lower as well, though the difference is not as dramatic as with the other pitches. Despite the “lower” release point, he’s nevertheless coming over the ball more, as illustrated by the horizontal release point graph above.
Chatwood only threw five curves against the Reds in that debut start, but he was able to generate about 45 percent more movement on it than last season. A few of these curves were thrown more over-the-top, but not enough to say, “Hey, look, Chatwood is finally getting on top of the curve!” So we need to wait and see how the rest of his starts go. All of Chatwood’s other pitches — especially his sinker, which was tailing 33 percent more compared to last season — displayed dramatically different release points, though.
In conclusion, the data from Chatwood’s opening start shows differences in release point. His curve release point difference isn’t as severe as all other pitches, but it was spiking more. As you’ve no doubt been yelling at your screen the whole time, however, this all comes from just a single start and we need to be careful not to extrapolate too much.
Knowing what we do about the Cubs’ pursuit of Chatwood and their desire to unlock the potential of his elite spin rate, this is definitely something to monitor going forward.