Seranthony Dominguez has a new (old) weapon

The bullpen for the Phillies has been questionable, at best, over these past few seasons. Watching them self-immolate on a near nightly basis brought back to mind one of the more iconic album covers in history, itself based on an iconic protest event. Yet this season, there was a more optimistic approach when looking at the collective group of arms. Corey Knebel was brought in as a true closer, Brad Hand and Jeurys Familia were added to help bring depth from the left and right sides, and Seranthony Dominguez was expected back after a long road to recovery from Tommy John surgery.

We all remember Dominguez as the once dominant arm from 2018, but the injury that happened in 2019, the lost season to Covid and visa issues and the recovery from surgery meant he hadn’t thrown a meaningful pitch in almost three years. Quite frankly, no one knew what to expect from him this season. Sure, there was a bit of an expectation that he’d be able to scale the heights he once did, but we weren’t sure how. The amount of weight he lost over the offseason certainly was a positive, but could we be sure he’d be the same pitcher he was in 2018?

So far, if his patterns continue throughout the season, the answer looks to be a solid “no”. Dominguez looks to be changing his pitch usage quite a bit, deviating from the four-seam fastball/slider approach he had three years ago to joining the new sinker/slider revolution that is happening before our eyes. Let’s first start by looking at his pitch usage patterns thus far in the season.

Dominguez has lowered his use of the four-seamer by about 10%, as well as dropping his slider usage by roughly 8%. In turn, his nodding affirmative for bringing the sinker has almost doubled. He’s shown it before, but never to this extent. You can see that in the past, he was throwing the pitch almost once every 11, 12 pitches, going even further down in 2018 when he was at the apex of his short career.

Why?

The first possibility to consider is that pitch classification has changed. In 2018, when Dominguez was throwing well, MLB was using Trackman to track balls in flight, both from the pitcher’s mound to off the bat and around the field. The switch over to Hawkeye in the 2020 season, as well as the tweaks that went into it, could have helped the system learn that what Dominguez was actually throwing was a sinker and not a four-seam fastball. So we have to at least consider the possibility that our robot overlords are simply learning as they go along.

However, if we go with the theory that the team has asked him to throw a new (old) pitch, then we can start to formulate some theories.

The first is that his four-seam fastball doesn’t have the same kind of juice it had three years ago. That long of a layoff will do that to a guy, but so will surgery. There are plenty of instances where a pitcher comes back from the type of surgery Dominguez had throwing as hard, if not harder, than before. So far this early in 2022, he’s actually posting velocity numbers a few ticks short of what he was then.

Average four-seam fastball velocity
2018: 98.0
2022: 96.1

Granted, he’s probably still regaining his lost stuff, but if this is where he’s at now, it’s not a bad thing. That 96.1 average four-seam velocity is still good enough to place him in the 90th percentile among all MLB pitchers, but it has also forced him to come up with something else.

It’s possible that in these past few years, the new coaching staff has looked at Dominguez and noticed that his fastball shape wasn’t good. You can see from this chart that in 2018, the movement on his pitches were some of the worst in the game.

If he wanted to continue as an effective reliever, either he had to develop something new, refine what he has or change the usage of what he already is capable of throwing. Apparently, he has chosen the latter route, his sinker rate rising in relation to his other pitches.

And it’s working. He hasn’t been hit hard much this year (though we’re only talking 16 batted ball events) and the two barrels he has given up were on sliders that he missed badly on.

But all of the other types of contact he has gotten, we see that it’s right in that sweet zone where not much damage is going to be done as opposed to those two blue dots we see from the slider picture.

We’re still dealing with small sample sizes here and things could change rapidly. It’s possible that he could regain that bit of lost velocity on his four-seam and suddenly favor the pitch. If it’s getting him out, more power to him. For now, though, he seems to have learned to lean a little more on pitches that can get him outs quicker rather than just always going for the strikeout kill. It’s something to keep an eye on as his season progresses.