The new Statcast metric that Luis Arraez dominates

Two-time batting champ leads MLB in squared-up rate

May 15th, 2024

Padres infielder Luis Arraez comes in last – last! – in bat speed of 216 qualified hitters on Statcast’s new bat-tracking data leaderboard, because he swings the slowest stick of anyone in the land. At just 62.4 mph, he’s 10 mph below the Major League average, and nearly 20 mph behind the fastest bats atop the leaderboard. He started a swing when you started reading this paragraph. It’s not finished yet.

Of course, he’s also the two-time defending batting average champion. He was being referred to as “the 21st-century Tony Gwynn” even before the May 4 trade that brought him to Gwynn’s Padres – a team for whom he’s struck out just twice in the nine games since he’s joined them. “Dude is a wizard,” San Diego outfielder Jackson Merrill told the Union-Tribune, in awe of his new teammate’s bat control.

The takeaway here is easy, then: Another new Statcast metric, another way that advanced stats don’t respect the best bat-to-ball hitter of his generation, right? Just like how his Baseball Savant page is full of blue (i.e., bad), because he doesn’t hit the ball hard, or run fast, or field well, right?

Not exactly. This group of metrics also comes with a way to quantify what you already probably knew: No one in baseball squares up a ball as well as Arraez does. He might “only” be a one-tool player, but it’s the tool that matters the most of any of them, and he might be the best in the world at it.

Allow us, then, to show you the Statcast leaderboard that Arraez is at the top of. Bask in the knowledge that you already knew that no one squared up the ball like Arraez did, and now the numbers completely support you in that. This is where Statcast doesn’t hate Luis Arraez. It’s where it absolutely loves him.

There should be two takeaways from that leaderboard, really. The first is: Here’s a way to put some love on the contact hitters of the game, and Arraez is the best of them. The second isn’t related to Arraez at all, but is impossible to skip past: Juan Soto is basically what would happen if Steven Kwan had a swing 11 mph harder.

For Arraez, what it means is that he’s getting the most out of his limited swing speed, and by the laws of physics, that essentially requires making contact with the sweet spot of the bat. Ninety-one different times this year, Arraez has made contact with a ball that Statcast defines as at least 80% squared-up. While that raw total rotates on a daily basis with Rangers second baseman Marcus Semien as the most in the game, it’s the most on a rate basis, which is to say: When Arraez chooses to swing, he is more likely than anyone to square it up.

What does that mean? Exactly what you think it does.

In order for a ball to be ‘squared up,’ a hitter must attain at least 80% of the possible exit velocity available to that swing, given the speed of the swing and, to a lesser extent, the pitch. You can’t do that off the tip of the bat. You can’t do it if you’re jammed on the hands. You can really only do it if you’re getting the fat part of the bat onto the ball – even if, as in Arraez’s case, that’s without elite swing speed. (The version of squared-up that does require excellent swing speed is called “Blasts,” and that’s currently led by William Contreras, ahead of Juan Soto and Shohei Ohtani.)

In his Padres debut, Arraez showed what a perfectly squared-up ball looks like.

When Brandon Pfaadt delivered an 88.2 mph fastball, Arraez replied with a 57 mph swing, which is 15 mph below the league average. That’s a huge limiting factor here; with a swing that slow, it wasn’t possible for him to deliver a ball hit harder than 90.5 mph at most, given the physics involved, and right away you can see why swing speed matters, in general. Without it, you have removed even the potential for the hardest-hit balls.

But Arraez hit that ball 89.9 mph, meaning he squared it up at 99% – he got almost every last bit out of the possible exit velocity his swing speed allows him – and his single to left field drove home Xander Bogaerts with the third run of the game.

He does it constantly, and endlessly. Earlier in that same game? Another 98% squared-up ball, again to left, off an even slower 55.8 mph swing.

Against the Dodgers on May 11? Another slow swing (63.4 mph), another swing that was close to perfectly squared up (97%).

Or how about this beauty, back with the Marlins, when a 62.4 mph swing turned into a 100% squared-up base hit?

The otherworldly contact ability is, essentially, a requirement at swing speeds this low. When you swing slow and don't square it up, it looks like, well, this.

Consider this: Arraez overwhelmingly swings below 70 mph, to the point that 95% of his competitive swings are under that threshold. It works, obviously, for him, because he’s such a king at squaring the ball up so well.

But for the sport as a whole, if you swing under 70 mph, and you can’t square it up? You are, essentially, doomed.

  • Squared-up: .318 BA // .446 SLG // .329 wOBA
  • Not squared-up: .122 BA // .134 SLG // .113 wOBA

Arraez doesn’t have the fastest swing; he has the slowest. He doesn’t have the longest swing; he has the shortest. He doesn’t run well (30th percentile in speed), or field well (1st percentile in Outs Above Average), and he certainly doesn’t hit the ball hard.

He just does this one thing, over and over and over, so well, better than absolutely anyone else alive, squaring up the ball on nearly half of his swings, better than any other hitter. Arraez is a one-tool player. That’s not an insult. It’s a compliment.