Finding CorbinBen Clemenson November 12, 2020 at 4:35 pm

I’ll admit it: I think about Corbin Burnes way more often than is healthy. Not in a Swimfan way, or anything; his blowup 2019 and standout ’20 are just my favorite example of a pitcher adjusting his pitch mix to match his natural talents, and Burnes has no shortage of talent. His fastball sits in the mid-90s with a naturally robust spin rate, and his slider turns batters into pretzels. He also posted a 6.09 FIP in 2019, driven by allowing 17 home runs in only 49 innings.

What was Burnes’ problem? While his fastball has a lot of spin, it’s not the same kind of spin as your average fastball. His fastball is heavy on gyroscopic spin — the football spin that gives sliders and cutters their signature “dot” — and light on transverse (or “active”) spin, which imparts movement. Of the 601 pitchers who threw at least 250 fastballs in 2019, Burnes’ active spin percentage ranked 585th.

That’s not a death knell for pitchers. The bottom of the list is dotted with sinker-ballers (the two types of fastballs are grouped together), and sinkers are unlike four-seamers in two ways. First, they have less transverse spin in general. Second, they don’t need as much transverse spin, because the effect they produce is a pitch that rises less than a batter expects. As they’re still thrown with backspin, less movement means less rise.

Burnes didn’t throw a sinker, though. He threw a four-seamer, and it spun in ineffectually. Fourteen of those 17 homers he allowed came on fastballs, and yeah, this is not a great pitch:

This exposition is getting a little long, but the point is that Burnes’ fastball wasn’t working for him, so he changed it. In 2019, he threw 53.4% four-seamers. In 2020, he threw the pitch only 7.4% of the time. In its place, he threw a sinker (31.9% of the time) and a cutter that took advantage of his natural cutting action (29% of the time). Suddenly, he was great: a 2.11 ERA and 2.99 xFIP garnered him Cy Young votes a year after he had trouble sticking on the major league roster.

Baseball isn’t that simple, but at times it can feel like it. Have two-seam or cutter spin on your four-seamer? Start throwing two-seamers and cutters! It helps to be prodigiously talented, and Burnes has always been that. He sports three secondary pitches that each induced whiffs on more than 40% of swings, and he pairs that with a mid-90s fastball with an absurd spin rate. You couldn’t make this change with a back-of-the-rotation journeyman and expect them to turn into Cy Burnes overnight.

Just because not every pitcher can’t do it, though, doesn’t mean none can. Let’s identify a few who fit the Burnes mold — a low-active-spin fastball with plus velocity and a handful of other good pitches. It’s too soon to say that this group would then be breakout candidates in 2021, but they’re the kind of pitchers that have the potential for sudden improvement.

To whittle down my list, I started with every pitcher in baseball and then began slicing. First, I got rid of everyone except the pitchers in the bottom 10% of active spin percentage. That left me with 42 pitchers, from A to Z, or more specifically from Shaun Anderson to Kyle Zimmer. Next, I got rid of everyone who threw sinkers at least 10% of the time. It’s not particularly interesting to see Framber Valdez and Dallas Keuchel on this list, because we’re looking for low-active-spin fastballs that can be turned into sinkers.

That left me with 23 pitchers. For my next cut, I emphasized Burnes’ pure stuff. We’re looking only for pitchers with above-average velocity. Burnes isn’t interesting because of his low active spin percentage; he’s interesting because that slight flaw was preventing his copious talent from showing through. No one’s interested in a guy who throws 85 with funky spin, at least in this exercise.

With those cuts out of the way, we’re down to 10 pitchers. The list still isn’t perfect, but we’re getting closer. Next, we need to find pitchers who already have the rest of the goods. Burnes wouldn’t be interesting with just a fastball; his slider, curve, and changeup are all usable secondaries, and that takes pressure off of the heater. It’s hard to construct a Burnes-esque season without his gigantic pile of strikeouts, and the breaking pitches are key there.

At this point, some of my cutoffs will be arbitrary. There’s really no way around it. Bottom 10% active spin percentage and above-average velocity were already arbitrary, and I’m just adding to it here — an unavoidable consequence of the way I’m searching. I decided to look for pitchers with two secondary pitches with whiff-per-swing rates higher than league average for that pitch, or one with a whiff rate at least one standard deviation above average. In plain English, I wanted a pitcher with multiple solid putaway pitches or a single dominant one.

First, a few honorable mentions. Ryan Pressly, Yimi García, and Tanner Scott are relievers who get by with their fastballs and make hay with their secondaries. They’re all borderline candidates, because I don’t think any of them are likely to retool their fastballs given their current form. None are at the extreme bottom of the active spin percentage table, and Pressly already throws fastballs less than half of the time. Still, they’re notable in their similarity, if nothing else, with García closest to meriting a change.

Next, we have a swingman who should probably be excluded. Chris Stratton fits our criteria, but only by technicality: his changeup induced a crazy amount of whiffs this year, but he only threw 54 of them (and got 24 swings). Aside from that, he doesn’t have a standout secondary, and he doesn’t really have a fastball problem. His active spin percentage is low but not unworkable, and he’s been consistently effective with the pitch — again, not much reason to change.

Then, we have our target. There’s one pitcher who fits all of these categories and also starts. Like Burnes, he has multiple plus secondaries and a fastball with plus velocity but less-than-ideal movement. His slider (which Eric Longenhagen gave a future 60) and curveball both did a good job inducing whiffs in a limited sample size. The slider also got a good amount of grounders, making it easily his best pitch.

His fastball, on the other hand, didn’t turn many heads. It was flat, in the fourth percentile for vertical movement, and suffered from a combination of low spin rate (2,277 rpm at 94.8 mph) and mostly gyroscopic spin. In fact, his 53.1% active spin percentage was even lower than Burnes’ 2019 campaign. Meet Johan Oviedo.

In practice, his fastball just looks flat too:

That’s not even a bad outcome, and it still looks like Luis Urías could have done more with it. That wasn’t an outlier, either: Oviedo consistently displayed bottom-of-the-barrel vertical break and didn’t make up for it with notable arm-side run. Not to over-percentile you, but Oviedo finished in the 10th percentile for whiff rate on his fastball, an uninspiring 13.2%. That’s not where you want to be with any pitch, but particularly not with a pitch he uses in the middle of the zone:

I’m not trying to say that Oviedo can’t survive in the majors with his current fastball. It’s not without merit: He commands it reasonably well, and the combination of his height and release point seem to create some natural deception. It isn’t a given that he could make the switch easily, and we’re looking at a small sample of 2020 major league appearances.

Minor league evaluators, who have had longer looks at Oviedo through the years, aren’t sure what to make of his fastball either. It’s alternately called a four-seamer and a sinker, and much of the focus has been on his velocity rather than whether it misses bats. That’s a reasonable take, particularly for a guy whom no one expected to see in the major leagues in 2020. Fine-tuning can come later; figuring out whether he throws hard enough and commands well enough takes precedence.

We might not get a chance to see whether Oviedo has tinkered with his fastball in the majors next year. The Cardinals have a decent amount of starting depth, and even if they weren’t quite so deep, it’s not as though Oviedo is knocking the door to the big leagues down. Eric had Oviedo’s ETA pegged at 2022 before this year, and he could do with a year at Triple-A to dial in his secondaries using the major league ball.

Whether or not he’s back in St. Louis next year, though, I’m interested in seeing Oviedo’s evolution. Pitchers have always made arsenal changes on the fly, but the modern flood of pitch-by-pitch data lets us speculate on it in real time rather than seeing what happened years later. Oviedo isn’t the most exciting find as potentially the next Corbin Burnes, but the fact that we can be on the lookout for them is victory enough for me. It’s of course not a given that it will work out as well here as it did for Burnes — after all, Burnes was a far better prospect than Oviedo is — but I think that Oviedo would be well-suited to try it out, and I’m excited to see how 2021 goes for him in either case.
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