Erik Swanson Is So Close, and Yet So Far

In 2019, Erik Swanson struggled quite a bit. Then, on Wednesday, Swanson’s five-run shellacking was another reminder that he’s continued to struggle pretty mightily. When the Mariners traded James Paxton, I can’t say I was thrilled with the return, but I understood that the market wasn’t exactly thriving for teams looking to trade a pitcher somewhat resembling an ace — at least relative to previous years. In any case, the headliner was Justus Sheffield, but it was argued that Swanson may actually be the superior pitcher of the two. After nearly two years to process the trade, that’s almost certainly not true, but Swanson seems like he’s only a tweak or two away from being quite overpowering.

That may seem like a weird thing to say. Swanson has a 6.43 ERA over 63.0 innings, and his 6.09 FIP suggests that his pitching woes have been all but deserved. He’s given up quite a few home runs — his 2.71 HR/9 is absolutely revolting — and it’s probably because he only has one good pitch.

Consider this fastball plot over his career, colored by percentage whiffs:

Obviously, Swanson’s fastball plays really well upstairs. On one hand, that may seem surprising, because he throws with average velocity and average spin when he’s starting. As a reliever this year, he’s bumped up the velocity by three ticks, but his spin rate has remained constant. That’s ravaged the Bauer Units of his fastball, but the bump in velocity and its other characteristics have helped it maintain its swing and miss.

The thing about Swanson’s fastball is that, aside from raw spin and velocity, it has a lot of good traits. His fastball’s 207-spin axis is nearly optimal, which allows him to throw it with 93.1% active spin that ranks him in the 93rd percentile of all fastballs. That allows him to throw a fastball with a lot of backspin, and really good ride. He’s any progressive team’s dream.

What’s not so dreamy about him is that his secondaries aren’t very good at all. In fact, they’re quite bad. His slider isn’t necessarily a disservice to him, but it absolutely should not be his best secondary offering. It doesn’t get chases out of the zone (28.9% chase rate), which leads him to to throw it in the zone (47.0% zone rate), which means it doesn’t get many swings and misses (8.7% swinging strike percentage). In the end, that means it’s not a pitch that gets hit hard, but because he can’t get whiffs with it, it doesn’t earn him any strikes. His slider’s CSW (called strikes plus whiffs) in 2019 was 19.3%, which ranks him second-last of 285 pitchers. That is so, so very bad.

And then there’s his changeup, which I would argue is worse. It’s essentially the same story as his slider. The difference is his slider, by pitch properties, doesn’t seem like it would be as poor of a pitch. His changeup does. In general, I would say that there exists no good changeup in a vacuum. It all depends on the velocity and/or movement differential it gets from one’s respective fastball. For Swanson, it gets none of the above. His changeup has a 7 mph velocity gap from his fastball, which is fine, but not around the 10 mph you would want to see. Horizontally, it gets almost zero separation, and vertically, just four inches (without accounting for gravity). This is all to say that his changeup, as is, is just a really bad, really slow fastball.

As is, his slider is better at getting whiffs up in the zone, to his arm-side. It’s sort of acting like a cutter in that way. His changeup just flat out against garnering whiffs at all. So, what does Swanson do? Well, change his pitches, obviously.

Given Swanson’s traits, he’s going to want some pitches with more drop. For his changeup, there are multiple ways to go about this, but Swanson is probably going to want to kill some of its spin, which should give it more drop, with less velocity. Another alternative — and perhaps this is what Swanson is going to need to do — is to just switch to a split change grip. These are infamously one of the more difficult pitches to command, but so long as he develops another pitch, that shouldn’t be an issue; especially because Swanson has the ability to throw his fastball so much.

As for his slider, the current composition of it clearly isn’t working for him, and I think it would be judicious to scrap the pitch in general. In talking to Nathaniel Plotts, he mentioned Ross Stripling as a potential comp for Swanson, and so a big loopy curveball with a ton of drop could be a strong potential option.

Consider Stripling’s deuce:

Easier said than done, but if he could throw something with this much drop, it would help his fastball play up and would undoubtedly draw a lot of strikes if he can command it well.

For me, I had more of a knuckle curve or spike curveball in mind.

This time, allow me to indulge you with Shane Bieber’s knuckle curve:

It’s one of my favorite pitches in baseball, and right now, it’s one of the best too. And so, in general, I think Swanson is best suited moving to a curveball, and if he does, he’s going to want one with a lot a drop like Stripling and Bieber have. With Stripling’s, it’s more of a pitch that he can drop into the zone for called strikes, whereas Bieber’s is more of a swing and miss pitch that he throws below the zone. Either way, they both induce a lot of ground balls, they don’t get hit hard, and they both go for a lot of strikes.

Unfortunately, this is all conjecture for the time being. I wish I could say there was some indication that this was something that Swanson was actually planning on doing, but for now, it’s all speculation on my end. Luckily, as one of the more progressive organizations in the league, I would be surprised if they didn’t tinker with Swanson over the offseason, but that’s assuming that they even keep him around next year.

It’s easy to feel down on Swanson right now, and that’s more than fair. With all of his struggles recently, I wanted to highlight that, with a few changes, he could still be an overpowering high leverage reliever, and I suppose there’s still an outside chance at being a starter, but those odds are looking more and more unlikely with every bad outing that passes. I recognize it may seem odd to argue that Swanson is “only” one or two significant changes away from being good, but as I said, he’s close! He’s just also so far.