For the most part, the Rays have received stellar contributions from their starting rotation this season. As of May 15th, their starters rank 5th in ERA (3.65), 2nd in IP (357.2), 9th in K% (19.6%), and 7th in WHIP (1.26).
Alex Cobb, the Rays #3 starter, was an unknown commodity - going under the knife for Tommy John in 2015 and not returning to the mound until September 2016 - heading into 2017. However, in terms of results, Cobb has looked improved to his old self on the mound, without his signature pitch.
Through eight starts, he has been awfully impressive for a man without his greatest weapon, compiling a 3.65 ERA, 1.28 WHIP and 31/13 K/BB ratio across 49 1/3 innings. The topic of discussion in this phenomena is the noticeable differences in the process of getting those results in 2017 compared to the rest of his career.
Earlier this season, Jim Turvey took a deep dive into Alex Cobb’s pitch usage from 2016-17, as compared to pre-Tommy John ace Cobb. Here’s a snippet of his writeup on prime (2013-2014) Alex Cobb:
Cobb threw a total of 186 four-seam fastballs over 309.2 innings. The four-seamer was nearly extinct from Cobb’s repertoire. Cobb’s sinker, which had been his tertiary pitch in 2011, was now his go-to pitch, with usage rates of 40% and 38% in 2013 and 2014 respectively. He wasn’t necessarily going to straight heat to start hitters off. In 0-0 counts over those two seasons, he threw 611 sinkers, 491 curveballs, 155 splitters, and just 69 four-seam fastballs. He was keeping hitters off balance right from the get-go.
Through Cobb’s first six starts of 2017 compared to prime Cobb, there was a large increase in reliance on his breaking pitches while his offspeed (the split-change) usage dropped off significantly.
For a deeper look, here’s data comparisons between his first six starts of 2017 and Alex Cobb from 2013-2014.
Cobb was noticeably relying on his splitter less. This wasn’t necessarily hurting him. His numbers were right around career-average. But if he wanted to revert back to Alex Cobb 2.0, he was going to have to regain his full arsenal.
The 29-year-old righty has made two starts since, posting a combined .160 opponents BA, 3.14 ERA, and 0.91 WHIP in two quality starts against Toronto and Boston, respectively. He has completely ditched his fourseam fastball, massively increasing his sinker frequency from 23.48% to 53.77% and noticeably increasing his curve frequency from 34.09% to 39.20%.
At a glance, the data suggests the right-hander is starting to regain form again - still without the past-dominant high-usage splitter - attacking and keeping opposing hitters off balance with a mostly sinker-curveball combination.
Obviously Cobb would like to get the splitter involved more, but it has induced some ground balls (3 ground balls on 14 thrown) over the two outings. Learning how to pitch with the sinker-curveball emphasis is getting a little bit better each time out. Now we’ll have to see if the splitter can join the improved arsenal at an increased level over the next few weeks.
Alex Cobb is still searching for his best pitch, the famous split-change that has thus far placed too much stress on his arm to throw in-game with frequency, but in exchange the right-hander has been fantastic at throwing all his pitches to all parts of the zone, and also just off it.
For now, Cobb has become a sinker-curveball heavy pitcher. And there’s nothing wrong with that. This is what good pitchers do: they adapt.