Red Sox bullpen led by Aroldis Chapman and Garrett Whitlock remains incomplete as Spring Training approaches

The Red Sox spent much of the offseason addressing the starting rotation. Boston added left-hander Ranger Suárez and right-handers Sonny Gray and Johan Oviedo, while also improving the lineup by acquiring right-handed power hitter Willson Contreras in a separate deal with the Cardinals.

Yet while the rotation and offense received meaningful attention, the bullpen remains an unsettled area of the roster.

Boston made only marginal additions this winter, signing five minor league free agents with spring training invites. While each arm will compete for a roster spot, they project more as organizational depth than clear Opening Day options. As spring training approaches, the Red Sox bullpen still lacks left-handers and another late-inning option. 

Entering camp, only four relievers appear locked into roster spots: All-Star closer Aroldis Chapman, Garrett Whitlock, Justin Slaten, and Jordan Hicks.

Greg Weissert and Zack Kelly should also factor into the mix, though both retain minor league options. Left-hander Jovani Moran is likely to break camp with the team due to the lack of left-handed relief depth on the 40-man roster. The other true lefty is newcomer Tyler Samaniego, acquired from the Pirates in the Oviedo trade. Pittsburgh had previously added Samaniego to its 40-man roster to protect him from the Rule 5 Draft.

Chapman enters 2026 coming off one of the best seasons of his career. The veteran southpaw was named an All-Star for the eighth time after posting a dominant 1.17 ERA across 67 appearances in 2025. He struck out 85 batters, recorded a career-low 0.70 WHIP, and at one point retired 50 consecutive hitters during a two-month stretch.

Boston rewarded Chapman with a one-year, $13.3 million extension that includes a club option for 2027.

The hard-throwing left-hander routinely touched triple digits and paired his elite velocity with a devastating slider that kept hitters off balance. 

Chapman also appears earmarked for Great Britain’s roster in the 2026 World Baseball Classic, while several Red Sox teammates are expected to participate, including Jarren Duran (Mexico), Ceddanne Rafaela (Netherlands), Whitlock (USA), and Suárez (Venezuela).

Whitlock’s outstanding season was somewhat overshadowed by Chapman’s brilliance. The 29-year-old made 62 appearances, logging 72 innings while allowing just 18 earned runs. He struck out a career-high 91 batters and allowed only two home runs throughout the entire season.

From July 4 to September 26, Whitlock ranked among the most dominant relievers in baseball. Over his final 32 outings, he posted a 0.58 ERA, collecting 17 holds while allowing just two earned runs in 31 innings. During that stretch, he did not surrender a home run, walked only five hitters, and struck out 41.

Whitlock’s performance solidified him as the club’s primary eighth-inning option and one of the few true constants in an otherwise fluid bullpen picture.

Beyond Chapman and Whitlock, Boston’s bullpen becomes far less stable.

Weissert appeared in a career-high 72 games and delivered solid production, posting a 2.82 ERA with four saves, 17 holds, 57 strikeouts, and a 1.16 WHIP. 

Kelly, meanwhile, showed flashes of dominance but struggled with consistency. He split time between Boston and Worcester and finished with a 4.58 ERA across 28 appearances.

Slaten should open the season in the bullpen, likely taking on a seventh-inning role behind Whitlock. Despite facing injury issues in 2025, Slaten achieved a 4.24 ERA, recorded 25 strikeouts, and maintained a 1.09 WHIP over 36 games. He ranked in the 86th percentile for both extension (6.9 feet) and fastball velocity, which topped out at 96.7 mph.

Boston will need to carefully