Abner Uribe and the Art of Landing the Slider

It doesn't take all that much to be a great pitcher, when you start with a triple-digit sinker with heavy action and ample arm-side run. Abner Uribe has those ingredients, and his slider is a nasty weapon, too, so he's never needed much of a third pitch. That said, last season demonstrated how thin the line between dominance and fungibility can be for a would-be high-leverage reliever. To become the co-relief ace of the resilient, playoff-focused Brewers, Uribe had to come back in 2025 as a more refined version of himself, even if that didn't mean adding anything to his arsenal.

The trick, to no one's surprise, turns out to have been to throw more strikes. Every pitcher should work to fill up the zone as much as is practical, but what's practical is different for every hurler. If you can throw 101 miles per hour with that aforementioned heaviness and a funky arm slot, there's virtually no point at which the returns on hitting the zone begin to diminish, but getting to the threshold at the lower end of that range—throwing enough strikes to be playable, let alone overpowering—is the challenge. When your arm can whip like that, getting the tip of the whip to land just right at the moment when you release the pitch is a monumental mechanical challenge.

This year, though, Uribe has solved that problem of biophysics. Here's a heat map showing the locations of his sliders in 2023 and 2024.

And here's the same image, for 2025.

Roughly 47% of the sliders Uribe threw to big-league batters in 2023 and 2024 ended up as balls. This season, between landing that pitch in the strike zone with so much greater regularity and (thanks to that demonstrated control and the tunneling effect of his better-located slider with the sinker) inducing chases, only 35.6% of his sliders have been balls. That difference is enormous, and for hitters, it's lethal. 

The interesting question, of course, is how he's achieved that improvement. Part of it can be ascribed to his maturity, which the team has universally and enthusiastically praised since spring training. He's brought a tougher and better mental approach almost every time he's taken the mound this year, which does show up in the way one repeats their delivery and (as a result) how well they can control the ball. 

Another part, though, is that Uribe has lowered his arm angle this year, partially by cleaning up his posture throughout his delivery. His average arm angle is down on each of his pitches, but the slider is where it's shown up most.

Here's Uribe missing with an 0-2 slider last March against the Mets. 

Brandon Nimmo is a good, patient hitter, but this also isn't a competitive pitch; it didn't even tempt him. Look at the position of Uribe's body and arm at the release point.

When you tilt your spine and fall off toward the glove side of the mound as much as Uribe did last year, it creates problems in commanding the ball—especially the breaking ball. With a high arm angle on a slider on which we was trying to impart mostly sidespin, Uribe made it very hard to hit any location other than the one where this pitch ended up, off the plate to that first-base side.

Here's a pitch on which Uribe got the Cubs' Matt Shaw to escape a huge jam in a key Brewers win last month.

Obviously, this is still a highly kinetic, athletic, even frenetic delivery. Subtly, though, it's much better-controlled. Here's where Uribe was when he released that pitch.

His spine isn't tilted as far, so his arm comes through under more control. With less of an exaggerated elevation in the arm slot, he could work around the ball better, without necessarily pulling it off the outside corner. This pitch almost backs up on him, in fact, but it has more than enough movement to frustrate a hitter and induce weak contact or a whiff, especially because it appears to start on the same trajectory as his sinker would. Here's another instance of him landing the pitch for a strike this year, against the Phillies.

Again, he can put plenty of white around that ball, not only getting it in the zone but giving plenty of cushion within it. This altered mechanical version of him has that ability to line up with the plate, and the sheer power and movement of his two key offerings make it relatively safe to do so. Many pitchers get hurt when they let a slider land on the inner half of the plate to a same-handed batter. Not Uribe. Even with the pitch pouring into the zone, this season, opposing batters have an average exit velocity under 80 miles per hour against it and are slugging .250.

Uribe is, perhaps quietly, the best pitcher on the Brewers this year. His 78 DRA-, at Baseball Prospectus, is bested only by Brandon Woodruff's 74, and Woodruff has only two appearances so far. His development as a person has been important, but so has his improved mechanical profile, and a better understanding of what makes his stuff great. Now that his slider can find the zone consistently, he's nigh unhittable, and he helps make the Brewers almost invincible if the game is close in the late innings.