Corbin Burnes and the Ways We Try To Make Sense of All of This

At the beginning of last season, my colleague Ben Clemens examined Milwaukee Brewers right-hander Corbin Burnes in something of a study into what pitchers can control, and which skills can be demonstrated fastest. Burnes had made just one start at the time, striking out 12 batters against one walk in five innings, while also allowing six hits including three homers. More illustrative than those results, however, were Burnes’ elite spin rates. Spin doesn’t take several outings to stabilize, and it isn’t something a pitcher flukes in and out of. Like velocity or foot speed, it is something one either possesses or doesn’t. Burnes has it. Ben’s a smart guy, so he hypothesized that it was likely those spin rates would help keep Burnes’ strikeout numbers high in future appearances, while his home run rates should taper off. Because really, who has that kind of stuff and still gives up three homers a game?

Well, in Burnes’ next start after that piece ran, he gave up three home runs again. In the start after that, he gave up another three. And in the start after that, he gave up two more. Then he moved to the bullpen, where he was fine for a couple of weeks — until Atlanta hammered three dingers off of him in just two-thirds of an inning. Burnes finished the season with 12.86 strikeouts per nine, and 3.12 homers allowed per nine. When opponents hit fly balls against him, 38.6% left the yard — the highest single-season HR/FB rate on record for anyone with at least 40 innings pitched. When he kept the ball in play, he was also historically unlucky; his opponents’ .414 BABIP was the fourth-highest on record. Burnes can say more about himself with a single pitch than just about anyone else, and yet his entire 2019 season only served as an example of all that can happen that’s outside a pitcher’s control.

Somehow, Burnes is having that kind of season again in 2020 — just in the opposite direction. Last year, he allowed 70 hits and 17 home runs in 49 innings. This year, he’s thrown 45.1 innings, and has allowed 22 hits and one home run. His 2.9% HR/FB rate is the second-lowest of any qualified starter, and his .233 BABIP is seventh-lowest. In a single year, he has transformed from, statistically speaking, possibly the unluckiest pitcher we’ve ever seen into the one of the luckiest of this season. What does that mean for Burnes, and for the way we talk about luck in baseball?

Luck plays a larger role in baseball than we often care to think about. In the 150-plus-year timeline of professional baseball in this country, it is only relatively recently that the challenge of parsing skill from luck has been embraced. ERA does an adequate job of telling you how a pitcher’s night, month, or season went, but it can be deceptive. FIP was an effort to tell you more about a pitcher than ERA can, but it can be deceptive too. Then we got xFIP, and SIERA, and Statcast’s expected statistics, and DRA, and other fine-tuned metrics all in an effort to do one thing — find a number that tells us the truth about what other numbers are lying about. It’s like sabermetricians are the FBI, and they’ve sent in a mole to infiltrate some group, only to decide they don’t really trust that mole anymore, and send in another to watch the first mole, repeating the process over and over again, and then somehow Jack Morris still makes the Hall of Fame.

Back to Burnes, though. Virtually any way you look at it, he’s probably baseball’s comeback story of the year. He’s turned an 8.82 ERA in 2019 into a 1.99 ERA in 2020. That’s great, but we still have other moles to talk to. His FIP in 2019 was 6.09; this year, it’s 2.03. Cool, Burnes is a way better pitcher now, unless the other guy has anything he wants to say. What’s that? His xFIP was only 3.37 last year, and is still just 3.21 this year? So he’s either in the middle of one of the most dramatic single-season turnarounds in recent memory, or he’s… basically the same exact pitcher he was a year ago. Awesome. Love this job.

Clearly, we have some work to do, so let’s try to identify what Burnes might be doing differently this year. Turns out, the answer is “quite a bit.” In his first two big league seasons, Burnes worked primarily off of his four-seamer/slider combination, with those two offerings making up nearly 85% of his arsenal last season. That shouldn’t be all that surprising — he has 99th percentile fastball spin, and the Brewers love to get their pitchers to throw rising four-seamers up in the zone. The problem, however, is that Burnes fastball stayed straight. It didn’t rise the way some other high-spin four-seamers do, and it tended to cut slightly. When he and his coaches regrouped in the offseason, they concluded that his fastball and slider simply weren’t getting enough separation. Burnes was a big fan of his slider, which meant the four-seamer — a pitch that, according to Statcast, allowed 13 homers in just 113 at-bats last season — had to go.

In its place, Burnes inserted a two-seamer, which would do a better job breaking in the opposite direction from his slider. He also began using a straightforward cutter, while backing off the slider and reserving his four-seamer as a “break glass in case of emergency” pitch:

“Well there it is,” you might be thinking. “If he’s throwing more sinkers, that means he’s probably allowing fewer fly balls, which would also mean fewer home runs.” That’s a good theory, until you find out that Burnes’ fly ball percentage is actually six points higher than it was last year. In fact, Burnes’ fly ball rate is the highest it has ever been, even going back to his minor league career. The guy with the worst luck in history on fly balls has responded by allowing even more flies, and now his home run rate is one of the lowest in the majors. Is anyone else’s head throbbing?

It isn’t that Burnes’ opponents suddenly can’t elevate the ball — it’s that they aren’t squaring it up as well when they do. A year ago, Burnes was allowing opponents to barrel up 11.7% of the balls they hit off of him, one of the very worst rates in the majors. This season, that figure is 8.8% — still subpar, but a lot more manageable. Opponents are generally hitting the same distribution of grounders and air balls they were last year, but now the quality of contact is much worse:

The contrast in the two seasons is even more stark in Statcast’s visual layouts. Here’s Burnes’ 2019 radial chart, followed by 2020’s:

That enormous clump of balls in the middle on the 2019 graphic? Those are bad news. Those are the hard liners and barrels that result in base hits in home runs. In 2020, that cluster is much smaller, getting broken up more into harmless flies, pop-ups and grounders.

This is where Burnes’ new two-seamer comes into play. Though it isn’t magically turning would-be homers into two-hoppers to second base, it’s been located in a way that makes it harder to crush than the four-seamer was. Take a look at these two charts showing Burnes’ pitch locations with his four-seamer in 2019, then his two-seamer locations in 2020:

The more you look at these graphics, the sketchier the idea of Burnes being historically unlucky in 2019 becomes. Sure, a 38% HR/FB rate is monstrous. But he was firing straight fastballs down the middle of the plate, and allowing hitters to square him up constantly — not just on fly balls, but also on line drives. Statcast ranked him in just the eighth percentile of expected slugging, and the 11th percentile of xwOBA. If you had to imagine what it would take for someone to basically give up a homer on two out of every five fly balls he allowed, this is the kind of guy you’d picture.

We ask metrics like xFIP and SIERA to be the voice of reason when other numbers are lying to us, but they confidently told us Burnes was either the 40th or 56th best pitcher out of 398 who threw at least 40 innings last year, and the whole time, he was getting crushed. And yet, those numbers are the ones that came closest to approximating what his production would be like in 2020. Only now, they are trying to temper enthusiasm. He ranks 11th in SIERA and 12th in xFIP, but seventh in ERA and second in FIP. He is the fifth-most valuable pitcher in baseball this season. The latter have alternated their understanding of Burnes between “free fall down an elevator shaft” and “superstar,” where the former have held tight to their belief that he is “pretty good.”

In that sense, I guess this is either a story about a pitcher who has risen from the ashes, or a story about one who is finally getting the results he’d always earned in the first place. Neither of those conclusions feel satisfactory to me, though; not when someone’s luck moves so swiftly from one extreme to the other. There’s something preposterous about the idea of the baseball gods jerking someone around like a bug in a jar, but it also feels ridiculous to think of a pitcher’s abilities alternating so haphazardly between awful and stupendous. Even as I volunteered to write this piece, I silently wished someone else were doing it — someone with a grip on math and formulas that I do not have, who could better explain how a pitcher stops an apocalyptic shower of home runs with a snap of his fingers. Instead, I’m 1,600 words into writing a baseball story, in awe at what I still don’t know.