This budding superstar has MLB's most dangerous swing

Brewers' Contreras leads MLB in blasts, a new Statcast bat-tracking metric

May 13th, 2024

Two winters ago, it seemed like a nifty piece of work for the Brewers to sneak into the Sean Murphy-from-Oakland-to-Atlanta deal, turning it into a three-team trade. It netted them catcher and reliever (plus prospect ) at the cost of only a speedy but light-hitting outfielder who had little future in Milwaukee’s talented and crowded outfield picture ().

Now, it’s a little more than merely "nifty." Instead, it seems like one of the biggest heists of the last decade, given that Payamps has blossomed into a high-quality arm in Milwaukee’s bullpen and Contreras has entered his name in the conversation for “The Best Catcher In Baseball," even ahead of Murphy. That’s in part because Milwaukee has gained a reputation as a place where catchers go to improve on defense, and indeed Contreras has done exactly that.

But it's a lot more than just the defense. We didn’t exactly need fancy advanced metrics to know that a catcher hitting a scorching .346/.429/.526 was having a superstar-level season, but on Monday, Statcast’s new wave of bat-tracking metrics gave us another reason to highlight what Contreras is doing for the first-place Brewers.

One of those new metrics is called a “blast,” and we’ll explain exactly what that means in a second. More urgently, it did not escape our attention that when we looked at who had the most this season, we had a list where "William Contreras is doing this thing better than Juan Soto, Shohei Ohtani, and Bobby Witt Jr.," and yes, that absolutely demands further investigation.

Most blasts, 2024 (through Sunday)

  • 58 // Contreras, MIL
  • 50 // Juan Soto, NYY
  • 46 // Shohei Ohtani, LAD
  • 46 // Bobby Witt Jr., KC
  • 45 // Salvador Perez, KC
  • 44 // Aaron Judge, NYY
  • 43 // Gunnar Henderson, BAL
  • 43 // Julio Rodríguez, SEA
  • 43 // Yandy Díaz, TB

It’s not just raw totals, either, because catchers don’t play as often as other hitters. Blasts per swing? It’s Contreras, ahead of Soto and Ohtani. Blasts per contact? It’s Contreras, ahead of Soto, Giancarlo Stanton and Ohtani. Right away, seeing any hitter above Soto and Ohtani tells you something about something, so: Hey, what’s a blast?

Milwaukee announcers were helpful enough to help illustrate when Contreras crushed a Mitch Keller sinker for a 448-foot home run on April 25, when they said “Contreras blasts one deep left-center field and way back,” because he sure did.

So what is this?

“It’s elite, I know that,” said Brewers co-hitting coach Connor Dawson, when asked about Contreras’ bat speed. “We know the bat speed is elite and it’s part of his tool.”

The advent of Statcast bat tracking has brought with it a number of new terms, and a blast, at its simplest, is the ability to square up a ball (which means to attain at least 80% of the maximum possible exit velocity available, given the speed of your swing and the pitch) and to do so with impressive bat speed. You can swing slowly and still square up a ball – i.e., the Luis Arraez starter kit – and there’s value in that.

This, however, is not that. This is squaring up a ball, with malicious intent. This is the list that has Contreras ahead of superstar names like Ohtani, Soto and Aaron Judge.

A "blast," then, is squaring up a ball, but with plus bat speed. (If you really care about the particulars, the strict definition is percent squared up 100 + bat speed >= 164,* but an easier shorthand way to consider it is that the average between squared-up rate and bat speed has to be at least 82 in order to be a blast. Simply put, while 25% of swings are squared up, only 10% of swings are blasts.)

If you’re wondering why any of this matters, it’s because the difference between a swing that results in a blast – and one that does not – is massive.

MLB swing breakdown

  • Blasts: .545 BA / 1.116 SLG / .705 wOBA / 99% hard-hit
  • Not blasts: .177 BA / .224 SLG / .175 wOBA / 17% hard-hit

You’d rather be in the group that has 900 points more slugging than the other, right? Of course -- and no one is doing it as much as Contreras.

“I think you’re born with some of that, no doubt,” said Dawson about Contreras' ability to find the barrel. “It’s in the blood.”

Perhaps it is, though it should be pointed out that while William’s brother Willson, the now-injured catcher for the Cardinals, has a slightly harder swing (75.7 mph) than his brother (74.2 mph), his 11% blast rate is less than half of William’s 25% rate.

For William, one out of every four times he swings the bat, he blasts it – squares it up, with good bat speed – and he’s hitting .621 with a 1.017 slugging percentage when he does.

“I do think a lot of it is just an inherent ability that he has that others don’t,” said Dawson about Contreras’ bat path and hand-eye coordination. “That’s a real thing. He doesn’t have to train that. It just exists.”

A blast can mean the ball is "scalded," as the broadcast described it, when a batter swings extremely hard and makes good-if-not-perfect contact, like this single where Contreras swung at 81.3 mph and squared up 90% of the possible exit velocity.

It can also mean when he swings somewhat less hard (73.8 mph), but gets all of it, a 100% squared up rate.

But the ideal is both, as Contreras did with the home run off Keller, which again was a 79.6 mph swing and squared up at 97%. You can see what it really looks like with a Statcast animation, because look where he makes contact on the bat – while swinging with intent. This was not a timid cut.

For Contreras, it’s really about the ability to keep the ball on the barrel while still swinging hard, which he's done about as well as anyone.

With just one-plus month of data, the story here hardly guarantees that Contreras will continue to absolutely mash all season long. We just don’t know yet, and might not for a while. On the other hand, it seems all but impossible to do something as good as or better than Ohtani, Soto and their peers on the leaderboards -- if even for only a month -- and not have it mean something.

After all, look at this comparison of average bat speed and blast rate, which can be turned into quadrants -- you don't want to live on the bottom left (slower swings, lower blast rate). You want to be in the top right, with fast swings and excellent blast rates. That's Contreras, grouped with the current gods of the game.

“He’s made huge improvements, right? He had a great year last year and was a really good player for us,” said teammate and 2018 NL MVP Christian Yelich, “but he’s really taken that next step offensively, defensively, baserunning. He’s committed to wanting to be the best version of himself and the best player he can be. Obviously he’s incredibly talented. I think he can really, really hit. He has a really good idea of what he’s doing up there.”

That much seems clear. We knew that before any high-speed cameras told us anything about the kind of contact he's making. Now, perhaps, we know a little more about how he's doing it.’s Adam McCalvy contributed to the reporting of this article.