Rising Through the Ranks
Some MLB prospects hit the ground running and never look back. Others need time to get their feet wet before becoming hot commodities. Miami Marlins prospect Karson Milbrandt falls into the latter category. After posting a 1.34 ERA with 70 strikeouts in 47 innings in Double-A this season, the Marlins’ No. 9 prospect on MLB Pipeline is heading to Triple-A.
The former third-round pick out of high school started his career struggling to work through professional lineups, but as time has gone on, the fast-rising prospect is one step closer to the big leagues.
A Journey of Improvement
If you’re an MLB franchise, all you can hope for is that the prep arms you draft continue to improve as their careers advance. Milbrandt has become the poster boy for steady improvement since first putting on a pro uniform in 2022. During his first full season in pro ball, the 6’2″ right-hander recorded 95 1/3 innings between A-ball and High-A. Across those innings, Milbrandt issued 50 walks with a .258 BAA and 4.74 xFIP.
While his potential was certainly noticeable, the Marlins farmhand struggled to miss bats in 2023, allowing an 83.7% contact rate on pitches inside the zone. Milbrandt improved his ERA and xFIP in 2024, but it wasn’t until 2025 that it became clear Miami had something in their former third-rounder. Following a delayed start to the season due to an elbow injury, Milbrandt struck out 101 batters and pitched to a 3.20 FIP in 77 1/3 innings in High-A to start 2025. With that, the right-hander earned a promotion to Double-A at the end of the season.
Milbrandt finished 2025 by registering an 8.4 K/9 and 2.40 xERA in his first 10 2/3 innings at the Double-A level. By that point in his career, MLB Pipeline had Milbrandt as the Marlins 18th-ranked prospect, but after a successful stint in the Arizona Fall League to finish 2025, the Missouri native looked like someone who could fly up those rankings in 2026.
Well, that has come to fruition for Miami, which has called up multiple prospects to the big leagues already this season. Using a fastball that can touch 99 MPH but sits averages 95, along with a strong slider, cutter, curveball, and changeup, Milbrandt has gotten his command metrics in check, while increasing his swings and misses and groundball rate. Prior to his recent promotion to Triple-A, the right-hander pitched to a 1.34 ERA with 70 strikeouts, a 3.26 BB/9, and 57.4% groundball rate.
A Closer Look at Karson Milbrandt’s Metrics
Now that he is headed for Triple-A, Marlins fans will be able to see pitch data for their budding prospect. Even without Trackman data on each pitch for this season, the metrics that are available for Milbrandt prove why he’s being considered a top right-handed pitching prospect. According to TJStats, Milbrandt ranks in the 99th percentile in whiff rate (42.6%), 99th percentile in swinging strike rate (20.4%), 98th percentile in CSW% (36.9%), and 96th percentile in wOBA (.246) among all Double-A pitchers to have faced at least 150 plate appearances.
Milbrandt’s Double-A metrics also show that he has no problem succeeding against both right- and left-handed hitters. TJStats has the NL East prospect in the 99th percentile in K% against lefties and the 98th percentile in K% against righties. Milbrandt’s stuff has proven capable of missing bats on both sides of the dish, with a swinging strike rate above 20% against both lefties and righties.
What to Watch For
If there is one thing to monitor at Triple-A, it is whether Milbrandt can get lefties to chase his pitches outside the zone. Before his promotion, Milbrandt ranked in the 99th percentile in O-Swing% to righties (37.3%), but in the same metric to lefties, he ranked just 28th (26.7%). This disparity caused Milbrandt’s walk rate to be nearly 10% higher for lefties (14.1%) than for righties (4.4%), per TJStats.
At the end of the day, Milbrandt has proven he can make the adjustments needed to further raise his ceiling, and now he’ll be looking to make those changes against another level of hitters.
