Dane Dunning Can’t Keep Getting Away With This!

The Texas Rangers, as you might have heard, are in first place. And that doesn’t even tell the whole story; the Rangers are currently on a 106-win pace, and believe it or not, they’re underperforming their Pythagorean record by four games. And they’ve done a lot of it without the best pitcher in the world.

Jacob deGrom, foremost among the numerous high-profile free agent arms Texas has invested in over recent years, has spent the past month on the IL with elbow inflammation. A slow recovery led the Rangers to move the two-time Cy Young winner to the 60-day IL on Monday. That precludes deGrom from returning to action before the end of June — which may or may not have been in the cards anyway.

But the Rangers have coped just fine without deGrom throughout May thanks in no small part to Dane Dunning, who started the year as a reliever but has matched deGrom’s results.

Even acknowledging that there is no pitcher quite like deGrom, Dunning could not be more different stylistically. None of Dunning’s pitches averages more than 90.6 mph. His strikeout rate, 16.6%, ranks just 104th out of 122 pitchers with at least 40 innings pitched this season. But among that set, he has the second-lowest ERA; only one other pitcher, Dustin May, has an ERA below 3.00 and a K% under 20%.

Dunning, 28, made at least 25 starts in each of the past two seasons before being displaced by deGrom, Nathan Eovaldi, and Andrew Heaney. He spent the first month of the season in a multi-inning relief role, where he was outstanding in a small sample — zero earned runs over his first six appearances, a span of 17 innings.

Shuttling back and forth from the rotation to the bullpen is nothing new for Dunning, who was something of a forgotten man on one of the most loaded pitching staffs ever assembled. (Yes, I’m going to talk about his college career, because the 2016 Florida Gators are one of my favorite baseball teams ever.) In Dunning’s draft year, Florida used 13 pitchers for more than one inning of work. Every single one of them got drafted, six of them — including Dunning — in the top 50 picks. Seven pitchers from that team have made the majors so far. The Gators also had Jonathan India and Pete Alonso at the infield corners. Absolutely loaded team.

With Logan Shore, Alex Faedo, and A.J. Puk in the weekend rotation, Florida used Dunning (as well as future first-rounders Jackson Kowar and Brady Singer) in a hybrid reliever/midweek starter role, and Dunning excelled. He finished third on the team in innings, and posted a 2.29 ERA and a 7.33 K/BB ratio. That got him drafted in the first round by the Nationals, who a few months later sent him to Chicago as the least important component of the Adam Eaton/Lucas Giolito trade. Four years after that, Dunning got swapped for Lance Lynn, which is how he came to be in Texas.

Invoking Puk and the Florida pitching development juggernaut makes Dunning sound like a power arm, but he’s not. And while his Location+ numbers and walk rate are good, they’re nothing out of the ordinary.

So how is this guy with a fastball velocity and strikeout rate out of the early 1990s keeping up with the best pitcher of his generation?

A couple months back, I had a lot of fun writing a piece called “What the Frig is Brent Honeywell Jr. Throwing?” in which I examined Honeywell’s changeup and screwball. For Dunning, the question is “What the Frig Isn’t Dane Dunning throwing?” Out of the 414 pitchers on Baseball Savant’s pitch arsenal leaderboard, 55 have registered six or more pitch types this season. (Yu Darvish and Chris Bassitt lead the league with eight.) But some of those are one-offs or possible coding errors. Dunning is one of just 17 pitchers who’s thrown six or more pitches at least 4% of the time this season:

Yeah, I picked that 4% cutoff mark for a reason. What are you gonna do about it?

Here’s another way to put it. Dunning doesn’t use any of his pitches more than 29.2% of the time. Out of those 414 pitchers, only 20 use their most common pitch less frequently than Dunning. Dunning throws all six pitches to batters on both sides of the plate, and this 1990s Wendy’s salad bar of offerings has led to similar results. Setting aside the curveball, Dunning’s other five pitches have led to an opponent wOBA between .233 and .306 and a strikeout rate between 12.5% and 24.4%.

The curveball numbers are a bit wonky because Dunning throws it exclusively early in the count. Out of all of his pitches, it’s the only one that sits outside the 82 to 91 mph range, and it has far more downward and glove-side break than his slider. You know, it’s a curveball. He’s thrown it just 34 times this year, and 25 of those have been on the first pitch of an at-bat. Having something weird to surprise hitters with for strike one is a useful skill, but the curveball is seldom the decisive pitch of the at-bat. Dunning has hit a batter with it, and produced five swings: three whiffs, a single, and a groundout.

There are three ways to look at the “How is Dane Dunning doing it?” question. There’s the technique approach, the predictive approach, and the descriptive approach. And from a predictive standpoint, I suspect that Dunning will not end the season with an ERA of 2.06. He’s got some concerning underlying numbers, like a career-low .265 BABIP (down from .338 and .313 in the previous two seasons), and a 69-point gap between his opponent wOBA and xwOBA. His xERA is 4.07, and so on.

Still, he’s keeping the ball off opponent’s barrels and not allowing many walks. If he does regress, it should be to merely league-average levels. And that leaves the descriptive question. Even if it doesn’t last, Dunning has one of the lowest ERAs in the league, and not just because of his hot start out of the bullpen. Dunning has an ERA of 2.28 since returning to the rotation, and despite a .314 BABIP, opponents have an OPS of just .588. And using that 40-inning cutoff, Dunning has a top-10 FIP in baseball too, despite not striking anybody out.

So what’s up? What kind of magic is he using?

Four statistics go into FIP: strikeouts, walks, hit batters, and home runs. And Dunning, in 48 innings pitched this season, has not allowed a home run. The only other pitchers to throw more than 30 innings and not allow a home run this year are Yennier Cano and Brent Suter. (Give ‘em hell, Brent Suter!)

Dunning isn’t giving out free passes, and while he does give up a lot of contact, the damage from said contact has been limited. Going back to that 40-inning cutoff, Dunning is 24th in baseball in GB/FB ratio, and when he does give up balls in the air, they don’t tend to be that dangerous:

Baseball Savant has 34 fly balls in the database for Dunning this year; the xBA on 21 of them was .075 or below. Dunning has given up four hits — a single and three doubles — on fly balls this year. And this was one of the doubles:

Most offense comes from balls hit in the air, and because Dunning isn’t allowing any damage, his opponent ISO of .051 is the lowest in baseball. Good luck scoring off a guy who doesn’t walk anyone or allow extra-base hits.

The Rangers will be without deGrom at least another three weeks, and given his history, Texas can probably expect to be without their ace for a good chunk of the remaining games. The longer Dunning can keep his opponents scrambling for singles, the longer the Rangers will be able to withstand deGrom’s absence.