Looking for Justin Verlander’s Curveball

Maybe it was all a setup for the headline, but in Anthony Fenech’s piece about Justin Verlander and his effort to return to glory — titled “Tigers’ Verlander ‘way ahead of the curve’ early this spring” — the pitcher points to the current state of his curveball as a sign of early success.

“I’ve seen a pretty dramatic difference,” he said. “The curveball seems to be a lot better already than it was at any point last year.”

Catcher Bryan Holaday, who stood in for the final few pitches of the session, agreed, saying the spin was nice and tight.

Verlander notices the difference, especially in the break, from last year, when his breaking pitches, “Neither one of those pitches was good at all last year. They didn’t have the same bite.”

Much of the previous analysis of Verlander’s poor year focused on his fastball velocity and fading release points. And the pitcher himself referenced those factors a bit when, later in the piece, he admits that he was underweight due to last year’s offseason surgery on his core.

But this might be the first time we’ve heard about the curve missing tightness.

Tight spin is a bit of a blind spot for PITCHf/x, in that spin is not observed, it’s calculated from the movement and velocity. But there is a calculated number for spin in the database, and we can also look at the movement and velocity of his curveballs over time as well. Maybe he was having some … trouble with the curve.

If you switch to the movement tabs, you might be unimpressed. Last year, Verlander’s curve was only about a half inch off when it came to horizontal movement compared to his career values. And his vertical movement and curveball velocity matched his career averages on the dot.

But even that cursory look is flawed — the curve had been better from 2011-2013, averaging seven and a half inches of drop. In 2014, he lost an inch more of drop off that average. It’s hard to see with the naked eye, but on average, his curve didn’t drop as much (2013 on the left, 2014 on the right).

That “little” bit of drop actually meant a great deal to Verlander’s curveball, it seems. That spin he references was off by about 200 revolutions off his average, and off 400 revolutions off his peak in 2011 and 2012.

We might be excused from not seeing this earlier, because his spin rates and outcomes on the pitch do not link up all that well. With the outcomes from Brooks Baseball, it looks like he’s had good spin rates and bad outcomes in the past.

This shouldn’t be a surprise, actually. There’s no correlation between curveball spin rate and swinging strike rate on the pitch (minimum 100 curves thrown since 2009, n=275, p=.81, r2=.0002). There’s barely a correlation between curve spin rate and ground-ball rate (p< .0015, r2=.0365), but that's not much to hang your hat on. When we looked at all curves, we found a general agreement between curveball drop and ground-ball rate, but Verlander’s grounder rate on the pitch was fine last year.

So that’s the weird thing here. Verlander is correct to say that the spin on his fastball wasn’t as tight last year. But it’s unclear how important that spin rate is. And his curveball has only twice been above-average for whiffs. It’s comfortably above-average for grounders, but it was also last year, when he didn’t have the same drop or spin as he did during that three-year stretch that came before 2014.

Sure, Justin Verlander’s curveball was lost, at least in terms of shape and feel. But in terms of results, it was about the same as it’s ever been. Funny how that works.