Let me open this by clarifying that I’m not accusing Tommy Nance of using foreign substances. Spin rate dips across the league are being interpreted as, “Hey look, he was cheating,” so I don’t want this post to be lumped in with everything else. Rather than imply anything, I’m simply stating that Nance’s spin rate has been significantly lower here in June.
In late May, Nance’s curveball peaked at an insane 3200 RPMs. But in his most recent outing, his curveball averaged ~2650 RPMs (~18% difference). Is the dip due to changing pitch grip procedures? Maybe. But, again, I’m not saying that’s the case.
Okay, so what is the case? Since we saw Nance’s latest curveball spin 18% less than his peak curveball, I wondered if his release point data could be one potential cause. Nevertheless, neither his vertical nor horizontal release point has deviated significantly lately, and his overall release extension has also been within his season range.
Nance’s recent spin rate dip is due to reasons we can’t observe with public data. For all we know, he may have simply sat on the plane wrong or slept on his hand funny and it led to the changes. Maybe something else mechanically is contributing to lower spin, but only the Cubs have access to that data. Whatever the reason, this is a trend worth following.