Trevor Rogers Changed it Up

© Brad Mills-USA TODAY Sports

Trevor Rogers was a revelation in 2021. He went from having a forgettable first major league season in 2020 to being a near-ace in short order, piling up strikeouts galore en route to a 2.64 ERA with the peripherals to match over 25 starts. You can’t throw a stick in Miami without hitting a pitcher who’s a potential difference-maker, but even against that backdrop, Rogers looked like one of the team’s brightest young stars.

This season hasn’t gone according to plan, to say the least. Rogers has been slowed by injury, hitting the IL thanks to back spasms and later a lat strain that shut him down for the year with the Marlins out of contention. But even when he wasn’t hurt, he struggled across the board. He struck out fewer batters, walked more, gave up 150% more home runs than in his 2021 campaign in fewer innings, and generally looked like a fish out of water.

If you’re painting with a broad brush, the story here is easy to understand. Rogers was better than expected in 2021, so our expectations got too high, and then he went back to his pre-breakout form. If you look closely, though, that’s not what happened at all. Rogers changed a ton about his game. Some of that change was good, some was bad, and I’m quite curious to see what sticks when he returns next year.

The most obvious change is the one I’m perhaps the most excited about. Rogers’ best pitch is a wipeout changeup, an indispensable weapon for a lefty starter without a deep arsenal. When he faces right-handed batters, he feeds them a steady diet of changeups. Why wouldn’t he? It’s both his best pitch and the best type of pitch for pitchers with a platoon disadvantage. It’s a no-brainer.

In 2021, Rogers mostly left it at that. He threw his changeup to lefties intermittently, roughly 20% of the time. He started off the same way this year. But over the past few months, he made a change:

Changeup Usage by Month and Handedness
Month CH% vL CH% vR
April 15.3% 29.8%
May 22.2% 34.5%
June 30.2% 26.0%
July 38.8% 24.1%
August 25.0% 37.5%
September 27.1% 29.5%

On the year as a whole, no lefty starter has thrown a changeup against lefties more frequently than Rogers. And that’s for the whole year, which includes several months of “normal” changeup use. In each month from June onwards, he threw more changeups than sliders to lefties.

Why do I like this new pitch mix so much? Easy: it’s good to throw your best pitch more often. Everyone knows that changeups play better against opposite-handed hitters, but that platoon effect is small relative to the fact that it’s a good pitch. Want the math? Among pitchers who have thrown at least 100 same-handed changeups and 100 opposite-handed changeups, the ones thrown to opposite-handed batters have comfortably done better, by 0.3 runs per 100 pitches.

Despite those pitches getting worse, though, they’re still effective. Among pitchers who had phenomenally effective changeups – I set the cutoff at -1.5 runs relative to average per 100 pitches, but you can set the line wherever you’d like – their changeups were better than average against both same- and opposite-handed batters. Of course they are – they’re good pitches.

Rogers’ changeup has been excellent against lefties, naturally enough. He runs an 18.4% swinging strike rate against them with the pitch, which is downright great. The pitch’s overall results against all batters took a dip this year, but I’d chalk that up to a small sample issue. The combination of fade and drop looks excellent no matter who’s at the plate:

Seeing Rogers throw his changeup more to lefties makes me excited about his future, because as I’ve already said, throwing your best pitch more often is always a good idea. Seeing Rogers throw his slider makes me puzzled. It was always his worst pitch, both by results and by scouts’ estimation, and that’s still true. It’s now a different pitch, though; he’s changed the shape of it completely:

New Slider Shape
Year Velo (mph) HMov (in) ZMov (in)
2020 81.2 1.0 0.5
2021 81.8 1.0 0.6
2022 80.6 4.3 2.8
HMov is reversed for ease of reading

His old slider was a slow bullet, which isn’t a good place to be. His new slider – well, it’s not quite a sweeper, but I suppose you could call it a baby sweeper. Its horizontal movement is several inches below average relative to similar-speed sweepers, but the pitch is at least doing something now. If he can continue to add movement, it could soon be an average breaking ball to complement his two already-excellent pitches.

One big benefit of adding horizontal break to his slider: sweepers carry larger platoon splits. I just talked about how Rogers should use his changeup more, platoon splits notwithstanding, but since he largely throws his slider to lefties, making the slider less handedness-resilient might pay off. If he’s mostly using the pitch as either a back-foot pitch to righties for use with two strikes or against lefties, giving it extra break makes perfect sense. Any improvement against lefty batters is worth a bigger downgrade against righties, because the old pitch wasn’t usable against anyone.

I still don’t think his slider is a great pitch. It needs more velocity or more break to resemble the best sliders in the game; as it currently stands, hitters have too much time to adjust to the movement and at least get a bat on it. But the sweeping, riding motion has paid dividends. He generated infield popups with the pitch like never before and finally got some swings on pitches outside the strike zone. His old slider mostly missed bats due to batters sitting on his fastball; his new one adds a bit of movement to the puzzle.

That fastball, which was devastating in 2021, looked mortal this year. The culprit, at least in my estimation: he got away from the shape that made the pitch play at its best level. He made a meaningful change in 2021, killing more than an inch of horizontal movement on the pitch, which helped it deceive hitters. He was, in essence, adding some cut to an otherwise cookie-cutter fastball. This year, that horizontal movement returned, and it apparently drove the pitch directly towards bats; his contact rate against was at a career high, as were the results on that contact, both actual and expected. It’s hard to make a living as a fastball-dominant pitcher, but it’s especially hard when opponents slug .739 against it (with a .715 xSLG, so it’s not like they’re getting lucky).

Here’s where this article drifts from telling you some facts about Rogers to speculation. Is it bad that his fastball isn’t shaped like he wants it? Absolutely. But he was hurt twice this year, and back spasms are the kind of injury that can mess with your consistency even before they send you to the IL. I’m willing to forgive some mechanical inconsistency for a young pitcher dealing with injury; it’s just par for the course.

If you agree with me on that, the rest of the package looks great. Rogers realized he could throw his best pitch more often overall, a great change. He realized that his slider is at its best against lefties and changed its shape to take advantage of that, also good. Two meaningful changes, and he was already wildly effective in 2021.

So while 2022 feels like a lost season right now, it doesn’t have to be. If Rogers can regain the feel for his fastball this offseason, the story could be different. What if 2022 was the year he learned how to best utilize his secondary pitches in an attempt to make up for a bum fastball, and 2023 is the year where the fastball comes back? He was even looking solid in August and September before the lat injury, which is always nice.

I don’t think that’s the only way this could go, of course. Maybe hitters have just figured Rogers out. Maybe his changeup/fastball combination just isn’t enough against right-handers, shape notwithstanding. Maybe changing his slider isn’t enough and he’ll need to add a cutter for variety. I’m not claiming he’s a fully-formed ace.

That’s not the point of this article. Despite bad results this year, I think Rogers did things that improve his long-term outlook. I don’t know if he’ll suddenly snap back to his 2021 form next year, but if he does, the changes he made this season while getting largely shelled will be a key reason why.





Ben is a writer at FanGraphs. He can be found on Twitter @_Ben_Clemens.

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Captain Moonlightmember
2 months ago

More. Same-handed. Changeups! We can build the whole ship out of em if necessary!