After struggling in the minors, the lefty had a breakout 2024 season
18. Luis Peralta (306 points, 25 ballots)
Peralta, who is indeed Milwaukee Brewers starter Freddy Peralta’s younger brother, is the highest debutant on this edition of the Purple Row Prospects list. The 24-year-old lefty reliever was acquired in the Jalen Beeks trade near the trade deadline last year in the midst of a breakout season, then he rocketed to a successful MLB debut. It was a sudden breakout, considering Peralta had been signed all the way back in July 2017 as a starter by the Pittsburgh Pirates for $110k.
Peralta didn’t come stateside until 2021 and wasn’t in full-season ball until 2022, after he’d already been eligible for the Rule 5 draft. Peralta struck out plenty of batters that year (14.5 K/9 rate) but struggled with run prevention (6.41 ERA, 6.6 BB/9 rate) and a starter’s workload (only 60 1⁄3 innings over 18 starts). Midway through Peralta’s 2023, repeating in Low-A ball, he was moved to the bullpen. He still struggled a bit with command (6.0 BB/9 rate), but he improved to 4.91 ERA while maintaining a healthy 11.0 K/9 rate. At this point, Peralta had already been exposed to the Rule 5 draft three times and had gone unselected and unprotected each time.
Then came the 2024 breakout.
Peralta’s 2024 numbers in Pittsburgh’s High-A affiliate were cartoonish: 0.60 ERA, 0.90 WHIP, 15.0 K/9 rate, 4.5 BB/9 rate in 30 innings. He was more human at Pittsburgh’s Double-A affiliate (1.86 ERA, 13.0 K/9 rate), but that was more than enough for the Colorado Rockies to acquire him for Beeks in a trade. In the Rockies’ system, Peralta continued to excel. Between five appearances with Double-A Hartford and one with Triple-A Albuquerque, Peralta threw eight innings of sterling relief — allowing one run on four hits and two walks with ten strikeouts.
Peralta finally made the Show in late August and he looked like he belonged immediately. He made 15 appearances for the Rockies down the stretch and didn’t allow his first and only run until the 14th of them. In total, Peralta pitched 12 1⁄3 innings, allowing only that one run (0.73 ERA) on seven hits and five walks (0.97 WHIP), striking out 14 (10.2 K/9 rate). Peralta’s 4.07 xFIP indicates some good fortune on run prevention, but the results were outstanding. His 0.8 rWAR ranked T-11th on the team (T-4th among pitchers) and his 0.3 fWAR was T-6th among Rockies pitchers.
Combined across three minor league levels and MLB, Peralta threw 60 innings in 47 games with a 0.90 ERA, 0.97 WHIP, 13.4 K/9 rate, and 3.9 BB/9 rate.
Here’s some of Peralta’s 2024 MLB highlights:
Eric Longenhagen of Fangraphs ranked Peralta 47th of the 92 prospects exchanged at the deadline as a 40 FV player, and last month he ranked Peralta 11th in the system as a 40+ FV grade pitcher with a 70 grade on his slider and a 60 on the fastball:
Peralta looked like a perfectly fine lefty middle reliever in Pittsburgh’s system before he enjoyed a substantial velo boost throughout the 2024 season, during which he was traded to Colorado at the deadline for Jalen Beeks. He sat 93 mph in 2023 and 94 during the bulk of 2024, then found another gear when he was promoted to the big club in late August and sat 94-97.
Peralta hides the ball well and creates upshot angle on the pitch; if he can command it to the top of the zone more consistently, it should be a comfortably plus offering. Peralta’s low-80s slider lacks raw spin, but it has still been a platoon-neutral weapon that generated a miss rate around 50% from both lefties and righties in 2024. If the velo spike sticks in 2025, he’ll be one of Colorado’s high-leverage options.
Baseball Prospectus recently listed Peralta as a “Person of Interest” in their system write-up:
Peralta isn’t as good as his sub-1.00 ERA, but throws 95 plus from the left side with a good enough breaking ball to stay employed as at least a second lefty in the pen for a while.
MLB.com ranked Peralta 30th in the Rockies system as a 40 FV player:
An undersized lefty who is now a reliever only, the 23-year-old Peralta is a two-pitch hurler. His fastball sits in the 94-96 mph range, and it can have some sink to it. His out pitch is a low-80s slider that misses a ton of bats, a key reason he had a 12.0 career K/9 rate at the time of the trade.
Peralta’s biggest hurdle has been finding the strike zone consistently. He’d walked 5.2 per nine in his career at the time of the trade, improving that to 4.0 this year. The key area of his development is landing his slider in the zone. If he can do that, it could give him a plus strikeout pitch and allow him to pitch meaningful innings in a big league bullpen.
Peralta has already been successful at the Major League level (though maybe more so than he deserved), so it’s not hard to imagine him continuing to be a useful set-up reliever going forward on the 2025 Opening Day roster. That’s why I ranked him 17th on my list as a 40+ FV player.