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 manage Slaten’s workload after he missed significant time last season due to a nerve issue in his neck that required surgery.

Hicks remains a lock largely due to his contract. The Red Sox owe Hicks $12.5 million in both 2026 and 2027, making a DFA highly unlikely. Acquired from the Giants in the Rafael Devers trade, Hicks struggled badly in Boston, posting an 8.20 ERA across 21 appearances with 12 walks, 15 strikeouts, and a 1.98 WHIP.

Unless Hicks is moved before Opening Day, he will remain part of the bullpen. A full spring training offers a chance for a reset, but expectations should be modest.

The raw tools remain intriguing. Hicks ranked in the 92nd percentile in fastball velocity (97.5 mph), the 95th percentile in ground-ball rate (56.7 percent), and the 93rd percentile in barrel rate (4.7 percent). However, his whiff rate (23.1 percent) and strikeout percentage (18.5 percent) ranked near the bottom of the league.

Simply put, he stunk.

Ryan Watson is one of the more intriguing additions. Boston acquired the right-hander from Oakland following his selection in the Rule 5 Draft, sending infielder Justin Riemer to the A’s in return.

The Red Sox had targeted Watson multiple times prior to the draft. The 6-foot-5, 225-pounder features a deep pitch mix that includes a four-seam fastball, sinker, splitter, slider, and curveball. His splitter gives him a second fastball look and helps his four-seamer play effectively at the top of the zone.

“We believe a deep mix, a big guy with good extension and good strike-throwing ability should translate to success in the big leagues,” Craig Breslow said after the trade.

Watson posted a 4.26 ERA in 46 appearances at Triple-A Sacramento last season, striking out 11.4 batters per nine innings while walking just 2.8. As a Rule 5 pick, he must remain on the active roster all season—or be offered back to the Athletics—making him a key roster puzzle for the Red Sox.

While Oviedo has been mentioned as a potential bullpen option, the smarter bet is penciling him into the starting rotation—especially if Boston ultimately trades Brayan Bello to improve the roster from an offensive standpoint.

Oviedo made nine starts for the Pirates last season after returning from Tommy John surgery and showed encouraging signs. The 6-foot-6 right-hander went 2–1 with a 3.57 ERA, striking out 42 batters across 40 1/3 innings.

One of the key traits Boston values is Oviedo’s fastball profile. His four-seam fastball topped out at 95.5 mph and featured elite extension (7.4 feet), generating a 31.2 percent whiff rate. His fastball with extension will play out of the bullpen if that's where the Red Sox decide he fits the roster best. 

Boston will bring five relievers to camp on non-roster invites, all of whom will compete for roster spots. While the odds are long, it has happened before. Sean Newcomb earned a rotation spot out of camp last spring, aided by injuries to Lucas Giolito and Bello.

Left-hander T.J. Sikkema is a player to watch, especially considering the limited left-handed depth in camp. The 27-year-old spent the 2025 season in the Reds organization, splitting time between Double-A and Triple-A. Boston also added left-hander Alec Gamboa on a minor league deal in December; he is a pitcher with both KBO and Triple-A experience who could contribute to the team's depth.

There are still options available on the free-agent market. Boston has been connected to left-hander Cionel Pérez and right-hander Seranthony Domínguez, and the club has also checked in on veteran reliever Tommy Kahnle. Justin Wilson remains a free agent and is currently considering whether to retire or play one more season, although he would prefer to pitch for a contender.

With camp opening in just a few weeks, Breslow faces pressure not only to add another bullpen arm but also to continue searching for offensive upgrades. The challenge lies in roster flexibility. Boston does not have many obvious DFA candidates on the 40-man roster, and difficult decisions are looming.

In fact, the Red Sox created roster space for Suárez designating infielder Tristan Gray for assignment and then trading him to the Twins for a minor league catcher. With Gray out of the equation, Boston has David Hamilton, Nick Sogard, and Nate Eaton as true utility-type players on the 40-man roster—limiting Boston’s flexibility for MLB-ready infielders. 

The Red Sox need more help, and the market still offers options. But time is becoming a factor. How aggressively Boston addresses the bullpen, along with its ability to find creative ways to improve the roster without sacrificing depth, may ultimately determine whether the team can make a meaningful step forward in 2026.