In 2011 and 2012, Alex Cobb established himself as yet another solid young starting pitcher for the Rays, going 14-11 with a 3.86 ERA in 32 starts and 189 innings pitched. His groundball rate was a great 57.1% and he managed a 6.8 K/9, a 2.6 BB/9, and a 0.7 HR/9, leading to a 3.73 FIP that inspired confidence that he could be even better. Yet as good as Cobb was, there was always something missing. He did a great job forcing groundballs and limiting the walks, but he was never going to be a pitcher that struck out a lot of guys and that limited his upside significantly. He threw a nice sinker in the low-90’s, but his curveball was more of a groundball pitch than a swing-and-miss offering, leaving only his split-change (changeup with a splitter grip) as a go-to pitch for him with two strikes. After just how good Cobb had pitched, he looked like he had the ability to be a good pitcher, but more of a number three or number four starter than a real top-of-the-rotation type pitcher. Now, though, there is increased reason for optimism. The reason: Cobb’s curveball. Cobb described it like this to Roger Mooney of the Tampa Tribune:
"Cobb is throwing more of what he calls a spike curveball, and the results produced a solid spring and 7 1/3 innings of shutout ball against the visiting Indians in his 2013 debut. Cobb, who faces the Red Sox tonight at Fenway Park, feels the curveball, which he throws by digging the finger nail of his right index finger into the seam of the baseball, has made a positive impact on his ability to be successful at the big-league level.“It’s huge,” he said. “Not only for a put-away pitch but it’s also, on the change-up I relied a lot on swings and misses hoping they chase out of the zone. This curveball allows me to start off the count early with just a get-me-over curveball, and usually they’ll take it if it’s not the pitch they’re looking for. So to be able to get ahead in the count is huge. I wasn’t able to do that so much with my change-up. It’s more of a hoping they chase kind of a pitch, and this one is more of an out of the zone in the zone.”"
Essentially, Cobb threw out his old curveball for a spike curveball with sharper break, and it has given him that second swing-and-miss pitch he has sorely been missing and allowed him to use his split-change less often and more effectively. Cobb debuted the curve last season, but it wasn’t until the end of the year that he really harnessed it, and now 2013 will be his first full season with the pitch at his disposal. How does the new curveball affect Cobb’s arsenal and does it truly mean that Cobb can strike out enough batters to become a number two-type starter? Let’s investigate that using one of my Pitch F/X graphs, with the data courtesy of Brooks Baseball but the graph itself being my own creation. Despite the altered curveball, Cobb’s pitch usage was very similar between 2011 and 2012, so we’ll compare 2011, the last season with the old curveball, to Cobb’s first outing of 2013.
We’re basically only worried about Cobb’s curveball (the red line) and his pitch usage on this graph, but there are a few interesting things with his other pitches that are worth pointing out. In 2011, Cobb actually threw his four-seam fastball more often than his sinker, but in his first start of 2013, we see that the four-seamer was basically was basically completely scrapped. The key says that he threw his fastball 18% of the time, but the lower velocity seems suspicious and the graph shows that the fastball was basically the same pitch (exact same arm slot to the decimal and trajectory), only the fastball didn’t move quick as much. It was only one game, but it’s something worth watching moving forward. Then you have Cobb’s split-change, which looks much better in the graph on the right with its movement precisely mirroring his sinker. Once again, it was a one-game sample, but if Cobb’s split-change has improved, it could be even more devastating pairing it with his newfound curveball. But is Cobb’s new curveball really so different?
When you look at the graph Cobb’s one start from 2013, we see that his curveball moved a little bit more down-and-in to right-handed hitters, and the key tells us that the pitch moved better even though Cobb threw it 2 MPH harder than he did in 2011. But is Cobb’s curveball really a “spike curveball” as he termed it? Absolutely not. Here’s a graph with a real spike curveball from Brandon Gomes (once again, the red line).
Cobb’s new curveball is a little over 1 MPH faster than Gomes’ yet has not too far off from double the vertical depth. They’re clearly radically different pitches. But isn’t Cobb’s clearly superior? With more velocity and more movement, it has the ability to miss bats while still having enough downward movement to force plenty of groundballs! But the net movement isn’t everything here. It would be convenient for my graphs if the definition of the “sharpness” of a pitch’s break would be say the velocity divided by the vertical movement. However, it isn’t. A typical spike curveball features later, sharper break somewhat similar to a slider. In order to break as much as it did, Cobb’s curveball had to begin breaking earlier, making it more recognizable and actually less of a swing-and-miss pitch. It basically got slurvy and got stuck in the no-man’s land between big movement and sharp action. What was the result of all this? Cobb threw it 22 times in his first start and could not manage a single swing-and-miss. Complicating things further is that the pitch’s big movement made it tough for Cobb to control as he threw it for a strike just 50% of the time, well off from the 62% mark he managed in 2012.
We’re only talking one start here, but based on the available data, I’m not buying that Alex Cobb’s breaking ball is any better than the groundball pitch it used to be. Maybe he changed his grip, but he’s getting basically the same exact results and swings-and-misses are not among that. Cobb noted to Mooney that he can throw it between 78-82 MPH, and maybe at 82 MPH it truly will become that sharp-breaking strikeout pitch Cobb needs to tie up his arsenal. But hold your horses before you think that Cobb’s breaking ball is so great and is quickly going to vault him to the next level as a starter. It’s simply not a great pitch at this point and as hitters adjust to it, Cobb will have to go right back to relying heavily his split-change for swings-and-misses. Cobb needs to work on perfecting whatever changes he made to his breaking ball, and until that happens, Cobb is no better than he was before. Alex Cobb is still an excellent middle-of-the-rotation starter no matter what happens and could succeed in such a role for a very long time. But before we think he can be more than that, let’s watch and see how good his curveball can be and determine whether it will really change everything for him in the coming years.