After an incredible July that saw the Boston Red Sox go 21-4, ultimately saving their season and propelling them into postseason position, the team has given key contributors time on the injured list to address lingering injuries. Among the players placed on the IL was right-handed reliever Justin Slaten, who was dealing with right elbow soreness.

After initially expecting to miss the minimum of 15 days or somewhere close to it, the 29-year-old continued to experience soreness as he began throwing progressions, leading the team to shut him down each time. On Tuesday, interim manager Chad Tracy announced that Slaten received a PRP injection to treat “degenerative changes in his flexor mass,” ending his season. 

With Slaten set to miss the remainder of the year, the pressure is on these pitchers to help bridge the gap between the starter and All-Star closer Aroldis Chapman: 

Guerrero was expected to be activated off the injured list ahead of Wednesday night’s loss to the Texas Rangers, but tightness in his lower back led the team to delay his activation. Still, though, upon his activation, Guerrero will become one of the primary seventh-inning options for Tracy to turn to. 

The 35-year-old flamethrower has been an incredible find for Chief Baseball Officer Craig Breslow, posting a 3.26 ERA in 38.2 innings in 2026. However, he hit a rough patch before landing on the IL, allowing eight earned runs in his last 13.2 innings. Boston will need him to return to the pitcher he was for the first 38.2 innings of his season, when he posted a 2.16 ERA. 

After not allowing a single earned run in his first 10 appearances after being dealt to Boston at the trade deadline, the 28-year-old lefty has struggled in his last six outings, allowing five earned runs, including three in a blow-up appearance in Wednesday’s loss. 

Miller told reporters after the loss that he was working through a mechanical issue that led to the struggles. However, he is the primary left-handed high-leverage arm before Chapman, so the team will need him to get those issues squared away ahead of what’s likely to be a Wild Card-round matchup against a New York Yankees lineup that’s lefty-heavy. 

No single pitcher has stepped up more for the Red Sox as they shuffled Garrett Whitlock, Slaten, and Guerrero on the injured list than Weissert. After a brief demotion to Triple-A Worcester on Aug. 7, Weissert returned to the big leagues on Aug. 13, taking Whitlock's spot on the active roster, and has been lights out ever since. In 10.2 innings since being recalled, the 31-year-old right-hander has allowed only two earned runs on 12 hits, striking out 14 and walking only four. 

Weissert figures to be the leader in the clubhouse to take over Slaten's role in the bullpen. 

The Red Sox have several pitchers looking to return from the injured list before the end of the regular season who could factor into the team's playoff push, including 2025 Cy Young Award runner-up Garrett Crochet, 2024 All-Star Tanner Houck, and Johan Oviedo. 

The 27-year-old ace has thrown four bullpen sessions since restarting a throwing progression on Aug. 3, with his most recent outing, a 30-pitch up-and-down session on the Fenway Park mound, coming on Tuesday afternoon. While Crochet, if healthy enough to appear in games, will almost certainly be on the postseason roster, he is expected to make multi-inning appearances rather than one-inning spurts like Slaten had been used, making him a valuable weapon but an imperfect replacement. 

The now-30-year-old right-hander is attempting to return to the Boston staff in a "Swiss Army knife" role after undergoing Tommy John surgery in August 2025. Houck has already made three rehab appearances with both Double-A Portland and Triple-A Worcester, allowing two earned runs on one hit, walking four, and striking out seven in 4.2 innings. He is expected to return to Worcester on Saturday for a 40-50 pitch outing before potentially rejoining the Red Sox. 

Though what exactly Houck can contribute after being out of major league action since May 2025 remains to be seen. 

A bit of a forgotten man in the 2026 Red Sox season is the 28-year-old right-hander, who made only one appearance before landing on the injured list on April 3 with right elbow inflammation. Oviedo will make his first rehab appearance Thursday night with Worcester before deciding on next steps; at this point, the risk likely outweighs the reward of making the postseason roster. 

Tracy, Breslow, and the rest of Boston's decision makers will have 10 games to make their final decisions on how exactly the postseason roster will look, and who will replace Slaten's high-leverage innings. 

The Red Sox will look to avoid the sweep at the hands of the Texas Rangers in Thursday's series finale from Globe Life Field. Sonny Gray (17-5, 2.76 ERA) gets the start for Boston opposite Tyler Alexander (5-2, 3.38 ERA) for Texas. First pitch is set for 8:05 p.m. ET.