(Photo by John Cordes/Icon Sportswire)

It’s easy to forget just how good Alex Cobb was at one point because it was so long ago. In 2013, he finished the year with a 2.76 ERA, 3.36 FIP, 1.15 WHIP, and an 8.41 K/9 over 143.1 innings pitched. Then, in 2014 he had similar success, pitching to a 2.87 ERA, 3.23 FIP, 1.14 WHIP, and an 8.06 K/9 over 166.1 innings pitched.

Then comes the dreaded Tommy John surgery, which caused Cobb to sit out all of the 2015 season and pitch just 22 innings in the 2016 season before coming back last year and pitching to a 3.66 ERA, 4.16 FIP, 1.22 WHIP, and a 6.42 K/9 over 179.1 innings pitched.

Now, that’s a pretty far cry from the dominance we saw from Cobb pre-surgery, and when you look more into his stats, you see even more reason to be concerned about the year he had last year, including the fact that batters are hitting him more than ever before:

And they’re hitting the ball harder than ever before:

And perhaps the most significant difference between Cobb pre-surgery and Cobb last year has been the strikeouts, which have plummetted:

And it all seems to link to one pitch: his split-change. Cobb’s split-change is one impressive pitch, or at least it used to be. In 2014 (the last year he was a full-time starter before the surgery), Cobb’s split-change had a 21.2 pVAL alongside a 53.1% chase rate and an 18.8% whiff rate. And even if hitters were able to hit the pitch, they only had a .218 wOBA and a .066 ISO against the pitch.

I mean, just look at this thing:

[gfycat data_id=”UnhappyMammothIndiancow”]

But last year was a totally different story. His split-change ended up with a -4.8 pVAL with a 40.8% chase rate and an 11.5% whiff rate. Still respectable numbers (aside from the pVAL), but not nearly what it was doing before, not to mention the fact that opposing hitters had a .310 average and .195 ISO against the pitch. In fact, it was so ineffective that he started using it less and less:

And it’s not like he lost control of the pitch or anything. Its zone rate last year was 33.7% which is actually better than its 2014 rate of 32.2%. And he didn’t lose any movement on it either, on the contrary, he actually gained a couple inches of horizontal movement. Its just hitters weren’t fooled by the pitch and it looks like the reasoning behind that is his vertical release point:

Cobb started releasing his split-change higher than he ever has before, and more importantly, higher than the rest of his pitches. As such, it’s been less effective and likely hitters are seeing the pitch better than they have before, which has led to them being fooled by it less.

Changeup struggles are actually relatively common among pitchers who have had Tommy John surgery; both Jose Fernandez and Stephen Strasburg had troubles with their changeups after surgery, though I should caveat that by saying that JoFer and Strasburg’s changeups were different pitches than the one Cobb throws.

Now that Cobb is with the Baltimore Orioles, he’s going to need to work on that changeup to be effective again. He was reasonably effective last year, but there are a lot of red flags that he’s due for some regression next year. However, if he’s able to rekindle the magic that was his split-change before his surgery, that regression might be a bit more limited and he might start actually earning that four-year, almost $60 million contract he signed.