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Examining the early success of Dane Dunning

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Dane Dunning has gotten off to a great start with the Rangers. Let’s take a look at how he’s doing it.

Toronto Blue Jays v Texas Rangers Photo by Tom Pennington/Getty Images

In what has been a mediocre start to what is generally expected to be a mediocre, at best, 2021 season for the Texas Rangers, we have striven to keep our focus on the fact that this is a rebuilding year, and that the goal for the 2021 is to see progress from young players and identify building blocks for the future. There are several young Rangers players who have given us reason for optimism so far this season*, but I think we’d agree that no Ranger has gotten off to a better and more encouraging start to 2021 than Dane Dunning.

* With the caveat, of course, that it is still extremely early in what will be a very long season, and we shouldn’t get too high or too low over anyone’s performance through the first dozen-plus games.

Dunning, acquired from the Chicago White Sox (along with pitcher Avery Weems) in the Lance Lynn deal this offseason, did not generate excitement among Rangers fans when the deal was announced. The view was, well, okay, I guess if that’s all the Rangers could get, then that’s all the Rangers could get, and we could lament the cratering market for rentals (even cheap, really good rentals like Lance Lynn) and resign ourselves to our fate as Rangers fans.

It wasn’t that Dunning was bad — he was a former first round pick of the Washington Nationals who was a consensus top 100 prospect before Tommy John surgery cost him the 2019 season, and he certainly pitched acceptably in 2020 for the White Sox, putting up a 3.97 ERA and 3.99 FIP in 34 IP over 7 starts. Its just that he’s, you know, passe. In 2021 its about high velocity, high spin four seamers and sharp breaking curve balls and Bugs Bunny changeups that generate whiffs. Dunning is a sinker/slider guy, a mix that has gone out of fashion the past few years due to those two pitches not having enough differentiation, and both tending to rely more on horizontal movement than vertical movement, making swings and misses less likely.

In Dunning, the Rangers got a guy seen as a high-floor, low-ceiling pitcher, someone with a good chance of being a back of the rotation starter for a number of years, but with little chance of being more than that. A team like the Rangers that, let’s be honest, has found it next to impossible to internally develop starting pitchers of any type over the last decade isn’t in a position to turn its nose up at a guy who seems like a solid bet to give you useful innings for several years while being under team control...but its an acquisition that lacked sex appeal. Lance Lynn coming off two Cy Young caliber seasons was something to dream on the return for...it wasn’t expected we’d be getting a Toyota Camry.

Here’s what one clown on the internet had to say about Dunning after the Rangers landed him:

Dunning isn’t a future ace or an exciting guy with a ton of upside. What he is is a guy with six years of team control who appears ready to be in an Opening Day rotation in 2021 and be a decent to solid back end starting pitcher.

Flash forward to today*, and a little over two weeks into the season, the Camry is exceeding all expectations. Dane Dunning is second in the American League in bWAR among pitchers, with his 1.0 bWAR behind only Tyler Glasnow. He’s sixth in bWAR among all American Leaguers**. His 0.60 ERA is second in the A.L., trailing Carlos Rodon, who has yet to allow a run in 14 IP, and is first in ERA+, apparently because Rodon’s 14 IP are too few for him to be included on the leaderboard. Lance Lynn, incidentally, has a miniscule 0.92 ERA — and he is still being outperformed by the guy the ChiSox gave up for him.

* I’m writing this on Sunday, so stats are through Saturday, April 17, 2021.

** Tied, weirdly enough, with Isiah Kiner-Falefa, who has an 81 OPS+, but who DRS has measured as being the offspring of Ozzie Smith and Mark Belanger through the early part of the season. Defensive stats are weird.

Dunning gave up a home run to the third batter he faced as a Ranger, Bo Bichette. He’s had 14.1 scoreless innings since then, over three games. In 15 innings of work this year, he has allowed 10 hits, walked 2, and struck out 16. That’s good.

If we look beyond the surface numbers, Dunning still impresses — he has a 2.29 FIP on the year, and a 3.15 xFIP. His 0.5 fWAR (which is based off of FIP rather than RA/9 like bWAR) is tied for 10th in the American League among pitchers (with Carlos Rodon and Hyun-Jin Ryu), and his 3.15 xFIP is 10th in the A.L. Prefer SIERA? He’s 9th in the A.L. there. His wOBA allowed is .211, and not surprisingly his xwOBA is higher — but it is still just .265, which is 16th among the 111 major league pitchers who have faced at least 75 batters this year.

So the surface numbers are good, and the underlying expected stats are good. Its a very small sample size, but over three games, Dunning has pitched well and gotten excellent results.

What I’m curious about, though, is how he’s doing it. Right after the Rangers acquired Dunning, I did a post about Dunning’s platoon splits, using a comment by Keith Law about his troubles with lefties as a jumping off point, and noting that Dunning needed to improve against lefthanded hitters. Looking at the Statcast data, I noted that while Dunning threw mostly his sinker and slider to righthanded hitters in 2020, he threw roughly an equal number of sinkers and four seamers to lefties, and used his change and curve much more against lefties than he used his slider. Fewer two seamers and sliders and more four seamers and changeups would seem to be the recipe for success against lefties, but he did that in 2020 and still had extreme splits.

Here is the conclusion of that post:

Dunning is not a high spin rate guy, and generally speaking, high spin rate is good for throwing a four seamer, as it results in less drop (and thus a “rising” effect, though the pitch doesn’t actual rise, it just sinks less). That said, I suspect the Rangers’ plan is going to be to have Dunning throw his four seamer more in 2021, particularly against lefthanded pitchers. If Dunning can command his four seamer and changeup, and gets comfortable using them against lefthanded batters, one would expect him to have more success against lefties — something that will be necessary for him to succeed going forward.

So when we go to Statcast and compare Dunning’s pitch usage in 2021 to his pitch usage in 2020, we see...he has stopped throwing his four seam fastball altogether. The pitch he threw 21% of the time in 2020, per Statcast, the pitch that I said I thought the Rangers would have him throw more in 2021, he’s not thrown once. His changeup? Also thrown less, 8.3% of the time in 2021 compared to 11% in 2020.

Instead, Dunning has gone back to being almost exclusively a sinker/slider pitcher so far in 2021. Per Statcast, 84.7% of his pitches have been either a sinker (65.3%) or a slider (19.4%). He’s thrown his changeup 18 times (15 to lefties), his cutter (which he either didn’t have or didn’t throw in 2020) 10 times (7 to lefties), and his curveball 5 times (4 to lefties). And it isn’t a result of the total pitch mix changing because he’s faced a meaningfully larger percentage of righthanded hitters in 2021 — he has faced 30 righties and 28 lefties in 2021, compared to 71 and 71 in 2020.

What has changed, however, is the results in 2021 — particularly against lefthanded hitters. Dunning allowed a .332 wOBA and a .346 xwOBA to lefties in 2020. So far in 2021, Dunning has allowed a .154 wOBA and a .240 xwOBA to lefthanded hitters. He’s actually been worse against righthanded hitters — a .264 wOBA/.288 xwOBA against them in 2021, compared to .204/.244 in 2020 — but he’s been so much better against lefthanded hitters it hasn’t mattered. In particular, his sinker has been better against lefties — he has a .133 wOBA/.242 xwOBA against lefties in 2021 with his sinker, compared to .267/.398 in 2020. His changeup and slider are also generating better xwOBAs against than in 2021.

The better results appear to be due to better command against lefthanded hitters so far. If you go to Dunning’s Statcast page, you can see visual representations of where his pitches have been located. In 2020, the heat map for Dunning’s sinker against lefthanded hitters was in the middle part of the plate, his changeup was consistently out of the zone low, and his slider consistently missed low and inside. In 2021, he has consistently located his sinker, slider and changeup low and away to lefthanded hitters. If you select “lefthanded batter” on the drop down menu, and flip back and forth between 2020 and 2021, you can see the dramatic difference in location between 2020 and 2021.

So what does this mean? Dane Dunning’s success in 2021 is due in large part to his dominating lefthanded hitters, after struggling against them historically. He’s done that by junking his four seamer altogether, and throwing sinkers to lefties about two thirds of the time. He’s had more success with his sinker by virtue of being able to more consistently locate it on the lower outside part of the plate, rather than out over the plate like he did in 2020. He’s also been able to locate his changeup down and away to lefties, meaning it looks like its down the middle before moving towards the edge of the strike zone, which can generate swings and misses to lefties, as well as using his slider as a back door pitch that starts outside before breaking in.

The $64,000 question is whether this is sustainable, and I don’t really have an answer to that, other than to say he’s probably not going to maintain his 0.60 ERA or 2.24 FIP, or even his 2.55 xERA or 3.08 xFIP. Dunning’s success has come over a 15 inning span, and that’s a tiny sample size to be dealing with.

However, Dunning has changed his pitch mix in 2021, and against lefties he’s either commanding his pitches better or changing where he’s trying to locate his pitches. If he can continue locating against lefties like he has in the first three games of 2021, Dunning seems well positioned to build on his strong start and potentially be an above-average major league starting pitcher.