The Red Sox made a series of roster moves Thursday morning, most notably reinstating right-handed reliever Justin Slaten from the 60-day IL. That move brings Boston’s 40-man roster to capacity. They’d previously had a vacancy after outrighting infielder Abraham Toro. The Red Sox also activated outfielder Rob Refsnyder from the 10-day injured list. To open active roster spots for Slaten and Refsnyder, they optioned southpaw Jovani Moran to Triple-A Worcester and placed first baseman Nathaniel Lowe on the paternity list (where he can spend up to three days).
Slaten, 27, is in his second season with the Red Sox after coming to Boston via the Rule 5 Draft in 2023. He was outstanding as a rookie in 2024, tossing 55 1/3 innings with a 2.93 ERA, a 25.9% strikeout rate, a tiny 4% walk rate and a strong 50% ground-ball rate. He’s had good results in 2025 as well, logging a 3.47 ERA in 23 1/3 frames, albeit with lesser rate stats. He’s been on the injured list since late May due to shoulder inflammation.
Slaten’s strikeout rate dipped to 17.8%, perhaps in part due to a significant drop in his slider usage. He threw nearly 25% sliders in ’24 but is down to 8% in ’25, instead favoring his curveball far more heavily (8.4% in ’24, 21.6% in ’25). Slaten’s walk rate has nearly doubled, up to 7.8%, but that’s still comfortably better than average. Sustaining a 4% walk rate was always going to be tough — it would be for any pitcher — particularly considering Slaten’s 8.5% walk rate in his final minor league season.
Even with some modest steps back this year, Slaten is a big arm who’ll provide a notable boost to Alex Cora’s bullpen. He’s been effective since day one in the majors, quickly pitching his way into a high-leverage role last year, and actually saw a bump in velocity prior to his IL placement, with his average four-seamer rising from 96.4 mph last year to 97 mph in 2025. He’ll join Garrett Whitlock, Justin Wilson and Greg Weissert as one of the primary setup options to closer Aroldis Chapman, who is enjoying perhaps the most dominant season of his 16-year major league career.