Jarrod Parker, Now Healthy

On May 7th, Jarrod Parker woke up with a pain in his neck. He’d been dealing with it for a while, and it had a lot do with his 7.34 ERA and the fact that he was giving up more than two home runs per nine innings. Those dark days are long since gone, but it was the low point for Oakland’s Game Three starter.

On Saturday before Game Two, Oakland manager Bob Melvin addressed those struggles and identified how that injury most hindered Parker. Even if that injury is in his rear view mirror, learning more about it might provide viewers something to watch for in the early going in Game Three.

Melvin said a few things about Parker’s struggles. The most important was that he suffered a neck strain some time in May — you can find notice of it in this game story after Parker gave up four home runs in Cleveland May sixth — and that the injury was “affecting him with his extension.” In related news, Parker “was getting in bad counts” and his “fastball wasn’t as good.” Given that all of this came in a two-sentence response when prompted about Parker’s early season, it isn’t a stretch to call these things related.

In the recap that mentions Parker’s neck pain, John Hickey says the pitcher had felt it for three starts. Given that he was removed from the middle of that Cleveland start, it might be safe to extend the neck pain period another start beyond that Cleveland start. That might feel like an arbitrary endpoint, but we know from a game recap of his next start (against Seattle, May 11th) that the neck was still bothering him somewhat. So to be safe, let’s call everything from April 20th to May 12th possibly affected by his neck strain. And everything after paint-free, at least as far as the neck was concerned.

What happened in that month that could have led to getting into bad counts? Let’s look at the fastball, since Melvin pointed us in that direction anyway. Courtesy Brooks Baseball, here are some stats on his sinker — his most common fastball — during and after his injury period.

The pitch got slower, traded horizontal movement for vertical drop, but didn’t get noticeably better at getting strikes, whiffs or ground-balls. It actually got worse at some things. This does not support any narrative about getting healthy.

Except that his home run rate dropped precipitously, and there was one aspect of the pitch that we didn’t report in that table. Release point. Parker doesn’t have the most steady of release points. During his injury period and after, his release points vary from 1.28 to 1.86 feet on the horizontal axis. He’s kind of all over the place, and that probably has a little to do with his control problems from time to time.

But let’s focus on his fastballs and changeup before and after the injury period, because those are his most important pitches.

Well, now that is interesting. Parker, with a neck strain, was releasing his fastballs further away from his head than he has since. And, since his changeup release point hasn’t changed, this fits what Melvin was saying. And, if you’re trying to keep hitters guessing between your fastball and changeup, it’s probably not a great idea to release the fastball two inches further away from your head than your changeup.

Maybe it doesn’t matter where exactly Parker is releasing his fastball with respect to his changeup. Maybe two inches isn’t enough of a difference to matter. Certainly the pitch peripherals suggest that there wasn’t much of a difference between Parker’s fastball in the two periods.

But it is still interesting to see this change in release point, considering that so many other aspects of his sinker didn’t change that much after his injury healed. Since the 20th of May, Parker has halved both his walk rate (from 4.7 per nine to 2.4) and home run rate (2.1 to 1.0). A big part of that has to be fastball control, and (probably also) a healthy neck.