Cobb’s Invisiball | The Process Report

Cobb’s Invisiball

This is not about a new pitch Cobb has added. It is about an old one that is missing.

Cobb has had three outings in 2017 and still looks more like the Cobb that came back late in 2016 rather than the one we saw before that fateful outing in the spring of 2015. The fastball velocity is back, and he is throwing his three pitches, but the surgical command of those pitches that we grew to love is not yet back. We know that pitch command is the last thing that returns for pitchers coming off of Tommy John surgery and Cobb’s two-year anniversary of his surgery only a few weeks away. The bigger issue is that his changeup appears to have been lost in transit somewhere as it has not yet arrived in the 2017 baseball season.

The changeup, a.k.a. “Thing 1”, has been Cobb’s moneymaker. Prior to his injury, Cobb utilized the pitch at least one-third of the time every season. It was frequently his preferred pitch to get ahead of batters and to either put them away or induce sub-quality contact. In the five starts Cobb made to close out 2016, he used the pitch 29% of the time, but this year, it’s been more infrequently utilized at just 20%. In fact, the changeup has been Cobb’s least utilized pitch this season as he has been using his breaking ball more frequently as he continues to wait for his changeup to come back. It is clear that Cobb is struggling with the pitch and does not trust it for him to reduce the utilization of the pitch by so much. Cobb even told Marc Topkin after an outing in New York as much:

“Get in those situations where I need that swing and miss, and that’s my best offspeed pitch right now,” he said. “You kind of learn to go with whatever the hot hand is that day. My whole career I’ve been changeup dominant and going to that when needing swing and misses and strikeouts.

“So I just have to relearn how to pitch a little bit using the curveball. It’s a great pitch. But I can’t wait for all three of them to be here.”

The reason the changeup takes longer, he said, isn’t as much the physics of the delivery as regaining the feel.

The numbers reinforce Cobb’s hesitancy.

The table below shows the number of changeups Cobb has used each season as well as the outcomes.

Season Pitches O-Swing% Z-Swing% Swing% O-Contact% Z-Contact% Contact% Zone% SwStr%
2011 250 52% 78% 62% 53% 92% 73% 41% 17%
2012 679 52% 79% 63% 60% 93% 77% 39% 15%
2013 682 52% 84% 64% 55% 88% 71% 39% 18%
2014 805 53% 85% 64% 53% 87% 69% 35% 20%
2016 121 39% 86% 55% 73% 84% 79% 36% 12%
2017 56 45% 78% 55% 65% 93% 77% 32% 13%

Since his return from the lengthy recovery, hitters are not chasing the changeup out of the zone at the same frequency they once did. They are not even offering at the pitch as often as they once did, which is a problem for Cobb because he rarely throws the pitch  in the the strike zone. When batters do swing at the changeup, they are making a lot more contact than in years past both out of the zone as well as within the zone.

Visually, the location frequency of the pitch has made a shift to the right. When Cobb is right, he is able to locate the changeup down in the zone; the great changeups tumble below the swing plane while the good ones avoid the contact in the sweet spot of the barrel. This year, the pitch is not finding competitive locations as much as it needs to, hence the reason batters are not offering at the pitch as they once did.

Previous work from Josh Kalk (now in Rays front office) and Dave Allen show a sweet spot for the difference between fastball and changeup velocity  between 5% and 12% slower. Cobb has maintained a very similar velocity difference between his two pitches. What he not maintained is the movement on his pitch. Good changeups have velocity separations, but the great ones have the movement too. Everyone that follows the Rays can close their eyes and visualize a number of such pitches from Cobb in year’s past where the pitch appears to fall off a table as it finishes its approach to home plate. Since coming back from the injury, that table is not there. In fact, Cobb’s fastball and changeup are way too close for comfort in terms of vertical movement.

What that means is Cobb is currently relying upon the velo separation of the pitch because more often than not, the changeup simply is not moving. When a pitcher talks about losing the feel for a pitch, it is in reference to being able to execute the pitch in a desired format. For Cobb, when he has the feel for his changeup, it is tantilizing batters to swing and it is diving out of the zone. Cobb currently does not have the feel for the pitch, has admitted as much to writers, and the effectiveness of the pitch is mostly dependent on the difference in velocity and consistent arm slot more than anything else. Lefties are lining up at the bat rack to face Cobb these days while that pitch is struggling as they have a .493 wOBA against him since his return from surgery compared to a .295 wOBA pre-injury.

Cobb could take off if and when the feel for the changeup returns. Until then, the types of outings he had in New York and Boston could continue. Tonight’s outing against a tough Houston lineup will be another tough test for the recovering hurler.

We wanted to bring in some of our new ball in play analysis for this piece so let’s switch gears to the other Jason, Hanselman, to take a look at what there is to see. After 56 balls in play this year Cobb is looking at an xwOBA* of .428, which is a little worse than average, but has seen an actual of .441. You could say that he has underperformed expectations, but it’s close enough that we’re not talking anything drastic. If he reverts to expectations then he’s stil a little worse than average, which may or may not be fine for the Rays. When you bring in his strikeouts and walks to go with the .428 xwOBA* I see a twOBA* of .377, which would rank 274th out of the 416 pitchers to allow a ball in play this year. Factoring in his workload to get wRAA he moves to 322nd out of this pool, which is not ideal. It’s early and there is time to right the ship, but so far he has been one of the lesser starters in the league. Let’s vizualize:

Over the course of the season he has shown some bright spots on the tails, but the middle was a very real problem. His actual has stayed fairly consistent in that average to a bit worse range, but this is where you should see more variance and that hasn’t been the case. Perhaps he has made the necessary adjustment or perhaps he just faced a very tough lineup that caused the spike. Time will tell, but so far there has been more bad than good, and plenty of both.

Switching over to his spray you can see some soft contact to the left, plenty of dribblers, as the excellent Andrew Perpetua describes balls below the origin, and then a rash of hard contact that dances all around the edges of the nitro zone. He mostly avoids the swoosh, but a lot of that hard contact should be expected to go for hits if not extra bases. As this piece focuses specifically on the split-change let’s isolate just those pitches marked as change ups that have been put in play this year:

He has allowed an actual wOBA* of .780 on the change so far, which is well above his expected, but at .551 his expectations aren’t all that great, either. This is a pitch that he needs to miss bats with, and when he doesn’t it’s getting whacked this year. While we cannot go back to the glory days when he was one of the most unheralded very good pitchers in the game, we can go back to last year when he was coming back from the surgery with mostly rough results:

Overall, he ran an expected of .439, which is a little worse than average, but his actual came in at a much worse .520. You can see that he was a little worse than average for both before settling in very nicely, and then running out of gas at the end. Here is his spray:

Again, we see lots of soft contact to the left of 90 MPH, and he does a good job of avoiding the swoosh. However, there are several balls in the nitro zone where you should expect to see massive damage. It would appear he is doing a better job of avoiding that zone this year, but it only takes a couple to wreck a line. Here is a focus on just the change:

Note that two of the three highest velocity balls in play he allowed were on his change and the couple of other nitro zones are also not so encouraging. The rest of the map looks quite strong. That shows up in his xwOBA* being at .422 for these 26 balls in play, essentially league average, and his actual was a slightly better .412. Even last year when he was initially finding the feel on this deathpitch he showed better expectations and results so it’s something that is getting hit harder this year. Not getting whiffs and seeing the pitch get hit harder when put in play indicates it is something he is still going to need to work on. Luckily, Cobb is as smart as he is nasty so I’d expect him to figure it out. It just might take some time.



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