The Boston Red Sox have yet to declare themselves buyers or sellers ahead of the August 3 trade deadline, though, at 38-48 and in last place in the American League East, many would argue they should be sellers. If Chief Baseball Officer Craig Breslow chooses to be a deadline seller, the Red Sox could find themselves in control of the deadline's hottest commodity: relief pitching. 

Anchored by Justin Slaten, Garrett Whitlock, and Aroldis Chapman, the Boston bullpen is one of the best in baseball. They'll enter Saturday's action with a 3.42 ERA in 310.2 innings, good for the third-lowest mark in the sport. All three of the Red Sox' highest leverage arms should be of interest to contending teams. 

Over the last two seasons, both Whitlock and Chapman have been among the most valuable relief arms in baseball. With a win probability added of 4.63, the 39-year-old Chapman ranks fourth among all qualified relievers since the start of the 2025 season, while the 29-year-old Whitlock is just behind Chapman with a mark of 4.44, which ranks fifth. 

After a dominant two-year run, Chapman has looked human as of late, allowing five earned runs on 11 hits over his last six appearances, good for a 9.00 ERA over that stretch. Overall, though, he has still been one of the best closers in baseball, posting a 2.10 ERA on the season. 

If made available, the 39-year-old figures to be one of the most sought-after relief arms on the market. Not only has Chapman been one of the best pitchers in baseball over the last two seasons, but he also serves as more than just a one-year rental for an acquiring team. If Chapman pitches just another 14.1 innings, bringing his total to 40, the mutual option on his one-year, $13.3-million contract vests, locking him in for the 2027 season provided he finishes the season healthy. 

Given his age and the possible impending lockout, the Red Sox would be wise to cash in on the 39-year-old Chapman in what is likely to be an extreme seller's market. 

In 28 innings, the 29-year-old Whitlock has allowed only eight earned runs on 23 hits, holding opponents to a .221 batting average en route to 13 holds on the season. 

Like Chapman, Whitlock represents a multi-year option for interested teams, as the 29-year-old has team options for both the 2027 and 2028 seasons at $8.25 million and $10.5 million, respectively. 

However, given his contract situation and age, it would likely take a massive haul of prospects to pry the 29-year-old Whitlock from Boston. 

After not allowing an earned run in his first nine appearances, Slaten has hit a major rough patch, allowing 13 earned runs on 24 hits in 15.2 innings pitched since being activated from the 15-day injured list on May 9. Overall, the 29-year-old right-hander has posted a 6.16 ERA over 19 innings. 

While a 6.16 ERA doesn't jump off the page as a valuable deadline asset, Slaten is striking out 11.84 batters per nine innings while walking only 5.7 percent of batters faced. Additionally, his expected ERA of 3.49 suggests he is due for positive regression. 

Slaten has four more seasons of team control after the 2026 season, so like Whitlock, it would likely take a lot to persuade Breslow to part ways with him. 

The Boston bullpen has also benefited from the success of 35-year-old Tyron Guerrero, who signed a minor league deal with the Red Sox over the offseason after spending the 2025 season with the Chiba Lotte Marines of the Nippon Professional League in Japan. Prior to 2026, Guerrero hadn't appeared in a major league game since 2019 with the Miami Marlins. 

The 35-year-old flamethrower has dominated since his return to the big leagues, allowing five earned runs on 14 hits, while striking out 21 batters and walking only one in 14.2 innings.

While Guerrero may not command the same return as Chapman, Whitlock, and Slaten, he is a trade chip that should be cashed in. 

The Red Sox have 25 games to play before the deadline; they will need to make up 5.5 games, jumping six teams to get themselves back into the thick of the wild-card race and avoid being sellers. They'll look to secure the series win over the Angels on Saturday night in game two of three from Angel Stadium. Sonny Gray (9-1, 2.69 ERA) will get the start for Boston opposite Sam Aldegheri (3-3, 4.85) for Los Angeles. First pitch set for 9:38 p.m. ET. 

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