Boston Red Sox

Red Sox bullpen outlook: Can relief pitching be a strength for Boston again?

Will Kenley Jansen and Chris Martin last the full season in Boston?

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Boston Red Sox spring training workouts are set to begin when pitchers and catchers report to Fort Myers, Fla. on Feb. 14. Full squad workouts begin on Feb. 19.

Ahead of spring training, we're assessing the Red Sox's situation at each position for the 2024 campaign. We'll break down the players expected to play the position for Boston in 2024, followed by a confidence grade. These positional outlooks will be updated as moves are made in the offseason.

In this installment of the series, we focus on the bullpen.

Brennan Bernardino, LHP

Bernardino came out of nowhere last season to give the Red Sox pitching staff a much-needed boost. The 32-year-old -- claimed off waivers from the Seattle Mariners in April -- was the team's primary left-handed reliever and thrived in his role.

Through 55 games (six as an opener), Bernardino posted a 3.20 ERA while holding opponents to a .250 batting average in 50.2 innings.

Bernardino will pick up where he left off as Boston's go-to southpaw out of the 'pen in 2024. His versatility will again prove valuable if the starting rotation is in flux yet again.

Brennan Bernardino
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Brennan Bernardino was quietly a key part of Boston's bullpen in 2023.

Justin Slaten, RHP

The Red Sox acquired Slaten from the New York Mets in early December. The Mets had just taken the 26-year-old righty from the Texas Rangers in the Rule 5 draft. Boston sent its 2023 10th-round draft pick Ryan Ammons to New York in exchange for Slaten, who must remain on the Red Sox's big-league roster for the entire 2024 season or be traded. Otherwise, Slaten has to be returned to the Rangers.

It's easy to see why new Red Sox chief baseball officer Craig Breslow is high on Slaten's potential. Last year, Slaten posted a 2.87 ERA with 13 strikeouts per nine innings through 40 appearances between Double-A and Triple-A. If that translates to the majors, Boston will have found another hidden gem.

Chris Murphy, LHP

We're including Murphy in here under the assumption that the Red Sox will use a second left-hander out of the bullpen. The 25-year-old is coming off an up-and-down rookie season for Boston, posting a 4.91 ERA and 1.41 WHIP through 20 appearances. His 3.70 FIP indicates he wasn't as bad as his bloated ERA suggests.

If he makes the team, Murphy will again serve in a long-relief role. There's reason to believe he can build off his promising debut campaign and be a reliable bullpen piece in 2024.

Isaiah Campbell, RHP

Boston shipped second baseman Luis Urias to Seattle in exchange for Campbell in November. The move flew under the radar after the Red Sox' letdown 2023 season and could prove to be underrated in hindsight.

Campbell shined out of the Mariners bullpen in limited opportunities last season -- his first year in the big leagues. The 26-year-old notched a 2.83 ERA and 1.22 WHIP with 33 strikeouts in 28.2 innings (27 games).

With John Schreiber (traded to the Kansas City Royals) no longer in the picture, Campbell has a chance to slot in as a high-leverage righty reliever. First, he'll have to beat out a few fellow right-handers who are competing for the job in spring training.

Isaiah Campbell
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Isaiah Campbell shined in a small sample size for Seattle last season.

Zack Kelly, RHP

One of many low moments for the Red Sox in 2023 was Kelly going down with a devastating elbow injury less than two weeks into the season. The 28-year-old, who has a history of serious elbow issues, was visibly emotional as he walked off the mound holding his arm.

Fortunately, the injury wasn't as serious as Kelly anticipated, and the righty is expected to return to Boston's bullpen mix in 2024. He'll be one of several righties competing for a spot, joining Campbell, Slaten, free-agent addition Cooper Criswell, and prospect Bryan Mata.

Josh Winckowski, RHP

Red Sox manager Alex Cora suggested Winckowski could make the team as a starter in 2024. He'll compete with Tanner Houck and Garrett Whitlock for that spot, but for the sake of this exercise (since we included Houck and Whitlock in our rotation outlook) we're treating him as a reliever.

A relief role seems to suit Winckowski best. The 25-year-old struggled mightily in the rotation during his rookie 2022 season, posting a 5.89 ERA through 15 games. As a reliever last year, he lowered that number to 2.88 in 60 appearances (one start).

We'll likely see Winckowski make some spot starts in 2024, but we'd be surprised to see him used consistently in the rotation after watching him excel in his role last year. He'll be even more important for the bullpen following the departure of Schreiber, not to mention the potential departures of Chris Martin and Kenley Jansen.

Chris Martin, RHP

Martin was simply incredible as Boston's set-up man a season ago. The 37-year-old veteran put up video game numbers in the most productive season of his eight-year career, boasting a ridiculous 1.05 ERA and 1.03 WHIP with 46 strikeouts and only eight walks in 51.1 innings (55 games). That effort was enough to earn him a Cy Young vote, which gave him a 12th-place finish for the award in the American League.

Chris Martin
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Chris Martin was the best set-up man in baseball in 2023.

As important as he'll be for the Red Sox in 2024, Martin can't be expected to duplicate those numbers. Regression is almost certain. But as long as he can hold up his end of the bargain and form a solid 1-2 punch with Jansen again, the 'pen could again prove to be Boston's biggest strength.

Martin's status will be worth monitoring leading up to Opening Day. Both he and Jansen have been the subject of trade rumors in recent weeks.

Kenley Jansen, RHP

Although Jansen isn't the shutdown closer he once was, he's one of the few All-Star talents left on Boston's unexciting roster. The 36-year-old was solid in his first season as the Red Sox' ninth-inning arm, amassing a 3.63 ERA with a 1.276 WHIP, 52 strikeouts, and 29 saves in 51 appearances (44.2 innings).

Barring a trade, Jansen will resume his role as Boston's experienced closer this year. If he's moved, we could see someone like Martin (if he stays) or Houck take his spot. The newly acquired Liam Hendriks is a candidate to take over the closing role if Jansen is moved at the trade deadline, which is when Hendriks is expected to return.

Bullpen confidence grade: B-

Boston's bullpen was its strength last season, but there are more question marks with this unit entering the new campaign.

With Schreiber already out the door, Martin and Jansen are prime candidates to be traded before Opening Day. The confidence rating for this group plummets if either arm is removed from the roster.

Then there are the inexperienced options. While Campbell and Slaten boast promising potential, neither has shown extended success at the big-league level. Kelly is coming off another serious elbow injury, Murphy has to be more consistent, and Bernardino needs to prove he wasn't a one-hit wonder.

As much upside as there is with this bullpen, there's real potential for things to go haywire. For that reason, it's hard to go any higher than a B- confidence rating.

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