Boston Red Sox Minor League Reliever of the Month - May 2025

[Billy Mock]

It's hard to come by solid high-leverage relievers that were drafted and are being developed as relievers. Fortunately for the Red Sox, they have one in High-A coming out of the back end of the bullpen for the Greenville Drive. Following an impressive eight-outing stretch in the month of May, Isaac Stebens is looking like a reliever that can be relied on in the big moment as he advances through Minor League Baseball.

Stebens was a 16th round pick (478th overall) to the Red Sox in the 2023 draft out of Oklahoma State. The now 23 year old right hander pitched exclusively out of the bullpen for the Cowboys, appearing in 28 games to the tune of a 2.24 ERA with six saves. It's uncommon that relievers are drafted in the upper rounds, so the Red Sox were able to land him late and really lean in to his skills as a high-leverage arm.

Stebens made his professional debut with Low-A Salem in 2024 where he appeared in six games before getting the call to High-A where he is now. In 35 appearances across the two levels last year, he appeared in 35 games, posting a 3.18 ERA and a 31.3 strikeout rate while closing out eight games. It was a great start to a career for Stebens, but he has seemingly gotten even better here in 2025, which was highlighted by a strong month of May. 

Stebens appeared in eight games out of the bullpen for Greenville in the month of May. Only three other Red Sox minor league relievers appeared in as many, and neither were quite as good as Stebens. In 11 and 1/3 innings, he allowed just three earned runs, which was good for a 2.38 ERA. Six of his outings were scoreless while three were across multiple innings, proving he can be an effective multi-inning reliever. In fact, Stebens delivered three perfect innings in an outing on May 17th against the Hub City Spartanburgers in which he struck out six batters across the fifth, sixth, and seventh innings. He struck out multiple batters in six of his eight outings, and there was only one outing in which he didn't log a strikeout. He finished the month with 22 strikeouts. which was good for a 44.0 strikeout rate.

Stebens's success has relied heavily upon his usage of his fastball and slider - a pretty common thing for relievers. His fastball sits in the mid-90s with some ride and plays up due to his delivery. The slider is a low to mid-80s offering with a lot more sweep than a traditional slider. There is a changeup in the mix that he added after he was drafted that he flashes from time to time and is working on. His control of the strike zone is fringy, which is one of the reasons he likely won't be stretched out as a starter, but after all, he is striking hitters out at a higher rate than he did in college at the moment. 

Heading into June, Stebens now owns a 1.99 ERA across 22 2/3 innings with a 35.6% strikeout rate while batters are only hitting .183 off of him. Among Red Sox minor league pitchers with at least 20 innings this year, his ERA, strikeout rate, and batting average against all rank within the top ten. If he continues to post these types of numbers throughout the year, Stebens may be able to establish himself as the farm system's premier bullpen arm. 

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