Dane Dunning and the mysterious case of the disappearing fastball

July 30, 2024

We’re almost done with National Statistical Anomaly Month, otherwise known as April. Broadly speaking, the target demographic for this month’s celebrations is anyone who appreciates the predictable comfort of a well-worn dad joke. A hitter blasts two home runs on Opening Day? They’re on pace for 324 home runs! Heyooo! Kyle Gibson allows five runs and only gets one out on Opening Day? That ERA of 135.00 is sure to break all kinds of records! Dane Dunning allows five runs in the third inning against the White Sox? That’s going to leave a mark. It’ll take him weeks to recalib—

… Oh. That’s fine, actually.

The ability to weather a game like that without dashing your stat line is the sort of cache you usually don’t get built up until around June. The fact that his season totals still look “normal” is a good indication of just how good the 26-year-old Florida native has been for the Rangers this season. Before that fateful inning, his ERA was an absurd 0.53 — a very “on-pace for 500 RBIs” number. By just about any measure you can think of, Dunning, whose services were acquired in the Lance Lynn trade this past offseason, has had a successful first month with his new team.

Last week, we took a look at Kohei Arihara’s seven-pitch repertoire. Today, we’re going to do the same for Dunning, showing you what each pitch does (and why he no longer throws a four-seam fastball).

Before we get to the pitch-by-pitch analysis, however, I’d like to take a look at his pitch overview, something made possible by Baseball Savant.

To understand what we’re looking at here, it’s important to note that the ovals that look like gears (or viruses?) over there on the right-hand side are the league averages. The smooth ones are Dunning’s pitches. Putting them both on the visual allows you to see how Dunning’s pitches compare to “normal” MLB movement for each pitch.

Speaking of league averages, back on the left-hand side, the league-average velocity for each pitch is notated by the little gray bars on the left-hand side that look like crosswalks. A brief overview shows us that Dunning’s velocity is slightly lower than league average, but his pitches move a little more than the average pitcher.

“Honestly, I view myself as someone who locates,” Dunning said after his April 17 start against Baltimore. “I’m not going to be able to blow a fastball by people, for the most part, so I gotta be efficient and locate as much as I can.

Let’s get to the pitch-by-pitch!

Sinker — 178 pitches (64 percent), average velo: 90.3 mph, average spin rate: 2,060 rpm

This is Dunning’s primary offering, and you’d be forgiven for thinking it looks an awful lot like a four-seam fastball. The difference is that it usually dips a bit at the end and cuts back towards Dunning’s arm side. Let’s go back to that chart at the top and look at what it says about the sinker.

Note that Dunning’s (smooth) circle is directly below the league-average (gear-shaped) one. What that means is that it has almost exactly the same horizontal break as a league-average sinker, but it “sinks” a little more. By using this pitch more than his others, the idea is to pitch to (bad) contact, which Dunning has done with quite a bit of success this year, even if his peripherals suggest a bit of good fortune: His xwOBA (expected weighted on-base average; here’s an explanation from last year) is .335, but the actual wOBA is .297. It’s not likely that teams are going to get hits on six out of every nine sinkers they put in play (as the White Sox did on Friday), but six hits on 30 sinkers put in play (Dunning’s pre-Friday totals, a .200 batting average) was probably a bit out of whack as well.

Slider — 58 pitches (20.9 percent), average velo: 80 mph, average spin rate: 2,128 rpm

It’s not the devastating low-90s slider like you might have seen from Matt Bush in his prime, but it’s still a pretty nasty pitch, given the late break. The glove-side break averages a bit less than sliders league-wide, but has 6.5 inches more drop than league average (which is why those yellow circles are so far apart on that chart up there.

If the sinker is Dunning’s most frequently-used pitch, the slider is his most effective: Hitters currently have a dismal .193 wOBA against the pitch, which probably isn’t sustainable but — remarkably — shows a bit of bad luck, since the xwOBA is a minuscule .125 on the pitch.

Part of that success is that Dunning picks his spots with the slider, throwing it twice as often to right-handers as left-handers (26 percent to 13 percent) and often throwing it as a put-away pitch with two strikes. Here, check out this chart of how often he throws each pitch in each count (orange is his sinker, yellow is slider).

If I were scouting Dunning, I’d tell hitters to ignore the slider with three balls, but look for it with two strikes.

Changeup — 21 pitches (7.6 percent), average velo: 84.5 mph, average spin rate: 1,967 rpm

We won’t waste a ton of space debating whether that particular changeup should have been called a strike or not — Austin Meadows’ facial expression has that conversation for us — but the movement is pretty easy to see: It breaks down and arm-side, as changeups tend to do. But where Dunning’s sinker and slider rely more on their vertical break to differentiate them from other pitches of the same name, his changeup drops a bit less than league average, leaving the horizontal break to carry the load. His 17.1 inches of arm-side break on the pitch is 2.5 inches more than league average.

When you consider how Dunning employs his slider (which breaks glove-side) primarily to right-handed hitters, it should come as no surprise that he throws the changeup more often to left-handed hitters (13 percent) than righties (3 percent). When you’re relying on guile above velocity, the ability to get a hitter to chase a ball away and either miss or hit the ball weakly on the ground is a pretty well-established path to success.

Of note: You might see the changeup more in coming starts, especially if Dunning starts to run into trouble again like he did against the White Sox.

“He could probably throw his changeup more; he could probably do some different things when teams start eliminating some (pitches),” pitching coach Doug Mathis said. “Because he has good stuff overall. So I think instead of just relying on his sinker and the slider all the time, he does have other stuff he can go to that we’re trying to encourage him to to throw a little more. Not not saying that he has to but just to kind of get it to his attention that ‘Your changeup is really good too; don’t forget about that pitch.'”

Cutter — 12 pitches (4.3 percent), average velo: 87 mph, average spin rate: 2,206 rpm

There’s a reason Dunning only throws the cutter 4.3 percent of the time; it doesn’t have the characteristics of a particularly-devastating pitch. The break is minimal, and when hitters make contact with it this year, they’re hitting 1.000 (2-for-2). If a 1.000 BABIP seems unsustainable, you’re not wrong, but the average xBA on those two balls in play — which left the bat with an average exit velocity of 104.7 mph — is .547 with an expected slugging percentage of .788 and he hasn’t gotten a single swing-and-miss at the pitch yet this year.

As we established in the lede, it’s still early, and these numbers aren’t likely to stay this bad. But thus far, the cutter is getting about as much usage as its performance warrants.

Knuckle Curveball — 9 pitches (3.2 percent), average velo: 78.9 mph, average spin rate: 2,173 rpm

Similar to Arihara, Dunning just doesn’t use his curveball a ton, and it appears to be used mostly as a change-of-pace pitch. But with just nine pitches to work with, it makes more sense to go back to look at how the pitch performed in 2020. It still didn’t get heavy use — he threw it 2 percent of the time to right-handed hitters, and 11 percent to lefties — but the results were markedly better last year, where hitters hit .000 against the pitch (they’re hitting .333 this year). He also had a slightly higher RPM on the pitch last year at 2,246.

In short, don’t expect to see a ton of curveballs from Dunning this year, but when you do see them, the results should be a bit better than they’ve been so far.

Four-seam fastball — 0 pitches (0 percent), average velo: 91.8 mph, average spin rate: 2,193 rpm (2020)

There’s a reason Dunning is wearing a White Sox uniform for the four-seam fastball video. Here’s the closest thing we could find to a 2021 version of Dunning’s four-seam fastball:

“I actually haven’t thrown a single four-seamer this year,” Dunning admitted after that start against the Orioles. “It’s by design. My whole emphasis last year, throwing the four-seam was to help me be more effective (against) lefties. And that was not the case. Lefties were batting, I think, .340 off my four-seam, so I decided to punt that, and I ended up establishing a cutter instead, just something to get in on the hands to lefties.”

So yeah, don’t expect to see that pitch this year.

One other thing I noticed while looking at Dunning’s 2020 repertoire: His walk rate has decreased in 2021 — 2.0 walks per nine innings, down from 3.4 last season. Part of that is to be expected when you see that he’s throwing more pitches in the zone this year (51.4 percent, up from 45.9 percent). But burrow down a level and there’s a neat little statistical nugget: He’s throwing first-pitch strikes 64 percent of the time, up from 56.3 percent last year.

I can’t help remember something Jose Trevino said about Joe Musgrove after he no-hit the Rangers earlier this month. He said that Musgrove established his off-speed stuff in the strike zone, so you couldn’t just ignore his secondary pitches. Once the Rangers started swinging at them, Musgrove would locate them just a little further away from the zone and induce some chase. We’re seeing something similar from Dunning this year. With the increased number of strikes thrown, he’s also getting a higher chase rate on pitches outside the zone: 27.4 percent, up from 23.9 percent.

It has been a recipe for success thus far for Dunning. We’ll see if he can keep it up as we head into May and the rest of the season.

(Photo: Richard Rodriguez / Getty Images)

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