Grant Anderson’s Breaking Ball Adjustments Have Helped Him Reach a New Level

Milwaukee’s bullpen is looking uncharacteristically shaky. After 25 games, Brewers relievers have combined for a 5.07 ERA over 94 innings pitched. Guys who were solid contributors last year (like Bryan Hudson and Trevor Megill) have failed to continue the momentum of 2024, and it seems like Joel Payamps is already past the point of no return. Funnily enough, Jake Bauers has the lowest ERA as a reliever, maintaining a perfect 0.00 from his two appearances.

Aside from the two-way hijinks of Bauers, there have been a few other bright spots in this year’s bullpen. Abner Uribe finally seems like he’s back in business, Nick Mears is finally posting numbers representative of his top-notch stuff measurements, and the call-up of Craig Yoho presents an exciting wild card to watch. One of the newest faces on the team is also off to a good start, thanks to some small tweaks that have had a big impact.

The Brewers traded for Grant Anderson during this past offseason, sending starter Mason Molina to the Rangers in return. To call Anderson a “project” would be understating things. After debuting for the Rangers in 2023, he accumulated a 6.35 ERA over the first 62 ⅓ innings as a big-leaguer.

The most noticeable problem was with his arsenal. His slider has been his primary weapon for the past three seasons, and it was never a very effective pitch in Texas, for several reasons. First, its velocity was unexceptional. It averaged just 82.2 mph last year, making it one of the slowest in MLB. Second, it didn’t move much. In 2024, Anderson’s slider had just 6.1 inches of vertical movement (nearly five fewer inches than the league average, and 7.0 inches of glove-side break. These unexceptional features gave opposing batters a batting average of .314 and a slugging of .514 against the pitch. When you pair this with a four-seam fastball in the low 90s and just 10 inches of induced vertical break, and you get a reliever with an 8.10 ERA.

If I had to take a guess as to what the Brewers saw in Anderson to make them want to target him in a trade, it would be his arm angle. It’s almost perfectly flat, averaging anywhere from -3 to 2 degrees. This unorthodox type of pitcher is exactly what Milwaukee aims to find and develop, and they almost never rock the boat too much once they get their hands on them. Rather than trying to turn Anderson into an over-the-top guy with a 12-6 curveball and a knuckleball that would make Phil Niekro blush, they chose to work with what they had and turn his slider into more of a sweeper. 

As a quick breakdown of the differences between a slider and sweeper, sliders are often thrown harder, with sharper and later break. Sweepers tend to have more gradual “sweeping” movement. The sweeper classification was introduced by Statcast in 2023 because, frankly, calling this pitch and this pitch by the same name doesn’t make a ton of sense. At the end of the day, pitching is a spectrum; no two pitches are really the same, anyway; Devin Williams throws a screwball, not a changeup, yada yada yada.

Back to Anderson. While Statcast still classifies his breaking ball as a “slider,” the movement profile is noticeably different.

By the numbers alone, you can see that Anderson has doubled the amount of glove-side movement he’s getting on his breaking ball, while inducing less vertical movement. He has also taken quite a bit of the velocity off to allow for more room to sweep. Let’s compare and contrast a typical slider from last year and this year.

As you can see, this pitch is flying across the plate with much more intent, and the outcomes have been largely positive. Opposing hitters are averaging just .048, with a whiff rate of 38.0% against his new sweeper and it has even made his four-seam fastball more effective. In addition to generally keeping batters on their toes with the sweeper, he attacks the lower part of the zone with the breaking ball and the upper part of the zone with the fastball, forcing hitters to change their eye levels constantly.

After 14 ⅓ innings as a Brewer, Anderson’s 3.77 ERA has room for improvement, but things are moving in the right direction. His FIP of 3.10 is a career best, and his overall ERA is largely inflated by a rough debut against the Royals, where he gave up three earned runs in 2 ⅔ innings. Not counting that first appearance, he has a 2.31 ERA over 11 ⅔ innings.

To me, this is the most fun part of being a Brewers fan. Watching an organization get the absolute best out of a pitcher seemingly at the end of his rope is what some might call “absolute cinema.” Now they just need to figure out what’s wrong with the rest of the bullpen, so they can get back to the top of the NL Central and dethrone those pesky Cubs (who are having bullpen issues of their own... but that’s a story for another time).