Rotation, Bullpen, or Nashville: Analytically Breaking Down Robert Gasser's Arsenal

Perhaps flying a bit under the radar, left-hander Robert Gasser might be the most interesting starting pitcher to watch in Milwaukee Brewers spring training this year.

Gasser came to the Crew with much fanfare, part of the package that came from the San Diego Padres in the Josh Hader trade at the 2022 trade deadline. Gasser had been a second-round pick of the Padres in 2021 out of the University of Houston and was the Padres' No. 7 prospect (MLB Pipeline) at the time. He was the biggest piece of the deal in terms of what he meant for the future.

After having been at High A with the Padres at the time of the deal, Gasser went up to Double-A with the Crew and made four starts before getting another promotion to Triple-A Nashville. He spent all of 2023 in Nashville, posting a 3.79 ERA, then started 2024 at Triple-A. He made three starts before getting the call to make his MLB debut as the Crew's No. 4 prospect.

When he did debut, he did not disappoint. In five starts, Gasser had a 3.38 FIP (2.57 ERA) with a microscopic 0.9% walk rate and a 14% strikeout rate (one walk, 16 strikeouts in 28 innings). But in that final start, he went five innings and gave up three runs, including his first two homers allowed, not looking as sharp as he had in the other four outings. It ended up being his final start of 2024 as he eventually chose Tommy John surgery, which would sideline him until the end of the 2025 season.

He came back to make two late-season starts and was included on the postseason roster. Thus bringing us to where we are today and Gasser's candidacy for Milwaukee's Opening Day rotation. With two open spots behind right-handers Brandon Woodruff, Quinn Priester, and Jacob Misiorowski, Gasser has the advantage as the only left-hander among the other contenders (Chad Patrick, Logan Henderson, Brandon Sproat). Sure, Aaron Ashby could be in the mix, but it would be hard to see him being removed from his key role as the top lefty out of the bullpen. DL Hall is another lefty who might get a shot, but he seemed comfortable in a relief role in 2025.

Robert Gasser's Stuff

Due to Gasser's limited time in the majors, a total of seven games and 33⅔ innings over 2024 and 2025, the data is fairly incomplete. The 26-year-old isn't a high-velocity guy, ranking in the 28th percentile with a 93.2 mph four-seam fastball. He does have an advantage with 6.8 inches of extension, which is in the 79th percentile. His four-seamer was on pace with where it was in 2024 before surgery, when it was at 93.3 mph. All of his other pitches were above their 2024 velocities, which is a positive now that he will have had a normal offseason to get ready for 2026.

In 2025, his four-seamer, sinker, and cutter were within solid margins of MLB averages for lefty pitchers, but his sweeper had 4.1 inches less drop, and his changeup had 2.6 inches more tail and 3 inches more drop, not good things when it comes to controlling the pitch. Again, this came in a very small sample of two abbreviated starts.

Robert Gasser's Pitch Arsenal

Gasser has a very traditional five-pitch mix: four-seamer, sweeper, sinker, cutter, and changeup. As a lefty, Gasser relied on his 82 mph sweeper in his 5⅔ innings in 2025 the most, throwing it 33.3% of the time. In 2024, the sweeper was at 80.6 mph and 32.1%. His 93.2 mph four-seamer and 92.9 mph sinker were each used 26.5% of the time, both up from 2024, when his 92.5 mph sinker was used 24.3% and 93.3 mph four-seamer 20.1%.

His changeup averaged 88.9 mph and was used 10.8% of the time, compared to 87.9 mph and 14.3% usage, while his 89.4 mph cutter was used a mere 2.9% of the time, as opposed to 2024, when it was 88.4 mph and 9.3%.

What Should Robert Gasser's Role Be In 2026?

Of all the candidates mentioned above, Gasser has the inside track to the No. 4 or 5 spot due to his pedigree and performance thus far, especially considering he is really the only lefty in the primary mix. While he still has three minor-league options remaining, Gasser should have a spot on the Opening Day roster one way or the other. If Hall, another lefty, surprises this spring in a starter's role and lands a spot, Gasser could go to the bullpen. Of course, both could grab the last two spots, although that is unlikely. Brewers fans should be looking forward to a full year of Gasser in the rotation.