Unreliable Bullpen Sinks Red Sox in Agonizing Series Against Blue Jays

After a series win in Cleveland, the Boston Red Sox headed into their series against the Toronto Blue Jays on a high, hoping to continue their two-game win streak. Unfortunately for the Red Sox, things did not go as planned. After a resounding victory in game one, Boston proceeded to drop the next two games, two contests in which they had a lead heading into the seventh inning—a series loss that came down to their weakest link: their inconsistent bullpen. 

Heading into the season, the Red Sox bullpen was in a good spot. In addition to the winter acquisitions of closer Aroldis Chapman and Justin Wilson, Boston’s bullpen was also boosted by relievers coming off productive seasons, like set-up man Garrett Whitlock and middle relievers Justin Slaten and Zack Kelly. 

However, as soon as the season began, the Red Sox’s past bullpen woes returned, coming to a head in their past series against the Blue Jays, in which Boston’s bullpen squandered multi-run leads into back-to-back games.

Red Sox Bullpen Has Been Unreliable

Garrett Whitlock’s first blowup in 2025 leads to game-two loss

After a solid Red Sox debut for Lucas Giolito, which saw him strike out seven and allow just three runs in 6 innings of work, Garrett Whitlock spelled doom for the Red Sox. Coming in with a three-rush cushion, Whitlock allowed four hits and gave up three runs in the form of a three-run homer courtesy of Anthony Santander. 

This was Whitlock’s first bad outing of the season. In the matchup, he was one of Boston’s best relievers, posting a 1.72 ERA in 15.2 innings. While not concerning in regards to Whitlock’s dependability, his poor performance, followed up by Slaten losing the game in the 10th, was a perfect representation of the Red Sox’s start to the 2025 campaign, as it has been the team’s own mistakes that have kept them in their way. 

Justin Slaten’s struggles continue, resulting in series loss

Despite being Boston’s worst pitcher to open up 2025, Tanner Houck threw a gem in game three, allowing just four hits and one run in 7 innings of work. Another quality start for the right-hander, Houck, has steadily improved since his disaster against the Tampa Bay Rays earlier in April. 

Still, Houck’s efforts weren’t enough. After coming in with a two-run lead in the eighth inning, Slaten’s scuffles continued, allowing three hits, including a game-deciding three-run homer by Vladimir Guerrero Jr. 

Outside of Zack Kelly (who has since been demoted to Triple-A Worchester,) Justin Slaten has seen the most significant decline in the Red Sox bullpen. After finishing with a 2.93 ERA and a 145 ERA+ in 55.1 innings in 2024, Slaten’s production has seemingly fallen off a cliff in 2025, as he currently holds a 76 ERA+ and 5.56 ERA in 11.1 innings of work. 

Luckily for Slaten– and the Red Sox, his advanced numbers show promise, and his 3.94 FIP indicates that he has been throwing competitive pitches, meaning his numbers should soon start to trend toward the figures of 2024. 

What’s next for the Red Sox?

Justin Slaten’s struggles in 2025 are a great representation of the Red Sox’s biggest problem: consistency. Unfortunately, this problem will have to work itself out, as many of Boston’s relievers outside of Slaten are having productive seasons, indicating that there is still a lot of untapped talent within the group. 

Hopefully, for the Red Sox, the return of Liam Hendriks and the promotion of top pitching prospect Luis Guerrero will boost the Boston bullpen because if the Red Sox want to win in 2025, the bullpen will be a significant reason.

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