Rays’ Alex Cobb Features Two Curveballs–But Neither of Them Can Last


It took a lot for Alex Cobb to become a regular starter for the Rays. Jeff Niemann had to hurt not once, but twice, in 2011 and then 2012, for the Rays to finally guarantee Cobb a rotation spot. He was different from the Rays’ other starters, never really a top prospect and not a pitcher with the ability to consistently dominate hitters win he’s right like the rest of the rotation. He was much of a groundball guy who struggled to strike batters out at times, but it didn’t matter because he was pitching so well. Between 2011 and 2012, Cobb went 14-11 with a 3.86 ERA, a 6.8 K/9, a 2.9 BB/9, and a 0.7 HR/9 in 32 starts and 189 innings pitched. Maybe he wasn’t going to be that ace-caliber starter, but he looked like a pitcher with a chance to be an excellent mid-rotation starter for a very long time. This spring, though, suddenly it looked like everything might be changing. Cobb had reportedly harnessed his curveball as a third plus pitch behind his fastball and split-change, giving him a chance to strike out more batters and pitch even better.

Last week, we looked into Cobb’s curveball, concluding that at least in the early going, it was not any real improvement over what it had been previously. Cobb said that his curveball, which he had made on a breakthrough on at the end of 2012, was a harder, spike curveball. While he did throw it harder, though, it was still more of a big-breaking pitch and not one that hitters would swing-and-miss at too often. That was a little disheartening, but in his next start, something became clear: Cobb was throwing two different curveballs. The best way to demonstrate that is to simply show you how they moved, so here’s a graph of Cobb’s two curveballs from this season and the old softer one he threw in 2011, with the data courtesy of Brooks Baseball and the graph being of my own creation.

Looking at the graph, we see the blue line, Cobb’s softer 2013 curveball, which was the pitch that he has thrown 39% of the time for the first pitch to opposing batters, more than any of his other pitches. It moved even more than his curveball from 2011 with big 11-to-5 break. Meanwhile, the green line, the harder curveball, was a pitch that Cobb has thrown 20% of the time with two strikes. It has moved significantly different from the softer curve, featuring less vertical break, more horizontal movement towards right-handed batters, and sharper 11-to-4 action overall. The three lines on the graph move in the same general direction, but the differences between the green and blue lines are noticeable enough to be divergent pitches. The curveballs shown on the graph do not account for all of Cobb’s breaking balls on the season (they’re about 65%), but comparing the 0-0 curveballs and the two strike curveballs was the easiest way to isolate the difference in velocity and movement between the pitches.

Speaking of velocity, the key tells us something interesting: although Cobb’s softer curveball from this year was over 1 MPH faster than his 2011 breaking ball, it had quite a bit more movement down-and-in to right-handed batters. Unfortunately, that isn’t a good thing. Cobb has thrown a ton of first-pitch curveballs but has only thrown them for strikes 53.7% of the time and generated whiffs on a puny 4.9%. Cobb’s curveball has done a decent job keeping hitters off-balance as they have swung just 5 of the 41 times he threw it and put it into play just twice, but he has not thrown it for enough strikes to capitalize. However, hitters not swinging at Cobb’s first pitch curveball is not a trend that’s going to persist because Not only has Cobb not thrown it for strikes, but he has done a terrible job commanding it. Here’s a graph of where Cobb’s first-pitch curveballs have ended up from Texas Leaguers.

No pitcher is perfect, but it’s scary how many of those pitches were left in the vertical middle of the zone or higher. You can compare that location plot to Cobb’s first-pitch curveballs from 2011 (and his 2011 curveball wasn’t even a very good pitch) if you want to confirm that curveballs aren’t supposed to end up in the upper portion of the zone as often as that.  Cobb has been able to get away with curveball in those spots because hitters have been sitting fastball against him. But if he keeps approaching hitters like this and missing his spots, hitters will sit curveball and drive those pitches a long way. These first-pitch curveballs certainly won’t overpower anyone, and Cobb hasn’t even kept them down well enough to force groundballs. This slower curveball from Cobb looks more like a show-me pitch more than anything else and not a pitch that will be effective at nearly the frequency at which Cobb is throwing it once hitters adjust.

The classic combinations for pitchers are fastball-curveball and sinker-slider. Alex Cobb has found himself right in between, throwing a sinker and a curveball. That may be changing. Even Cobb’s harder breaking ball has been classified by Pitch F/X as a curveball, but nonetheless it features sharper movement along the lines as a slider and has shown flashes of being that second swing-and-miss offering Cobb has been sorely lacking behind his split-change. In two-strike counts so far in 2012, Cobb has actually forced whiffs at a higher rate with his curve compared to the split-change, 14.3% of the times he has thrown it versus 12.5%. Despite that, though, Cobb continues to rely heavily on the split-change with two strikes, throwing it 35% of the time compared to 45% for his sinker and just 20% for his curveball, and that trend holds true for both lefty and righty batters. You can contrast that with a pitcher like Jeremy Hellickson, whose curveball has come on this season and allowed him to actually throw it more than his devastating changeup against left-handed batters even if his change remains his go-to pitch against righties. If Cobb’s hard breaking ball has been effective, why isn’t he using it more often? The answer is that he’s having trouble throwing it for strikes, hitting the zone 57.1% of the time. That isn’t such a bad number, but considering he has thrown his split-change for a strike 91.7% of the time, it’s easy to see why he would go to that more often. But there’s a major problem that’s behind Cobb’s mediocre strike-throwing ability on his changeup: he can’t throw it within the zone. Glancing at Texas Leaguers graphs, just 3 of 12 of the harder curveballs that Cobb threw were quality pitches in the zone (I didn’t count pitches in the upper stretches of the zone which were obviously hangers). It was a solid chase pitch, but Cobb couldn’t throw it for an actual strike even if he wanted to, and hitters will recognize that before long. And combining that with what we said above about Cobb’s slower curveball and it immediately becomes clear what the problem is.

Pitchers everywhere add and subtract velocity from their curveball based on the count and that’s something can make those pitches more effective when used correctly. However, Cobb’s curveballs go far beyond that. He can throw one only for a get-me-over offering to get ahead in the count and the other is a pitch with which he can little but bury it in the dirt. And when the difference in velocity is as much as 2 MPH and the change is movement is even more noticeable, we’re getting to the point where batters could, if they identified Cobb’s curveball out of his hand, be able to guess fairly accurately whether it would be a ball or strike based on the count. Even if Cobb tries to mix them up more and use them in different counts, it’s a situation where hitters may even be able to identify which pitch is which based on how it begins moving, and that’s a scary thought. Alex Cobb has to decide what his curveball is going to be. Is he going to keep using it as the decent change-of-pace groundball pitch it has been the last few years or is he going to try to throw it harder and try to use it to overpower hitters? And once Cobb does that, can he find a way to use it both in and out of the strike zone? Those are questions that Cobb will have to answer over the remainder of 2013 and will loom large in determining whether Cobb’s future is as a back-of-the-rotation starter or something more. Until Cobb can address that, all he has is a pair of inconsistent pitches that he will have to use less and less as hitters adjust to them.