Ahead of Sunday’s game in St. Petersburg against the Tampa Bay Rays, the Boston Red Sox activated right-handed reliever Tyron Guerrero from the 15-day injured list. After being placed on the IL on Sept. 1 with right shoulder inflammation, the hard-throwing 35-year-old will have spent just over the 15-day minimum on the IL after experiencing a minor setback earlier in the week. 

After spending the 2025 season with the Chibbe Lotte Marines of Japan’s Nippon Professional League, Guerrero signed a minor league deal with Boston ahead of the 2026 season. In his first major league action since 2019, the 35-year-old flamethrower has been a revelation for the Boston bullpen, posting a 3.26 ERA in 38.2 innings.

In his first year in Boston, Guerrero has become one of the many poster children for the pitching infrastructure being built in Boston under Chief Baseball Officer Craig Breslow and Andrew Bailey. After walking 5.7 batters per nine innings in his first three seasons in the big leagues from 2016-19, Guerrero has harnessed his electric stuff, walking only 1.6 batters per nine in 2026, the 11th-lowest rate among relievers with at least 30 innings pitched.

Despite the fantastic results, the rest was definitely welcome for Guerrero. After posting a 2.16 ERA in his first 24 appearances of the season, the 35-year-old was showing signs of wear, allowing eight earned runs in his last 13.2 innings of work before landing on the IL. 

However, his return comes at the perfect time for a Red Sox bullpen that just lost Justin Slaten for the remainder of the season after interim manager Chad Tracy told reporters on Tuesday that the right-hander received a PRP injection in his right elbow. 

To make room on the active roster for Guerrero, Boston optioned Wyatt Olds to Triple-A Worcester. 

Olds pitched well since being recalled from Worcester to take Guerrero’s spot on the major league roster. The 27-year-old right hander allowed only two earned runs on seven hits while striking out 12 and walking four across nine innings. In two stints with the major league team in 2026, Olds posted a 1.20 ERA in 13 appearances spanning 15 innings, making a late case to make the playoff roster. 

With the Triple-A season ending on Sunday, Olds will likely head down to Ft. Myers to join the Red Sox playoff taxi squad. 

The Red Sox will look to win the series against the Rays and clinch a playoff spot in Sunday’s series finale from Tropicana Field. Veteran left-hander Patrick Sandoval (1-6, 4.99 ERA) will get the start for Boston opposite righty Griffin Jax (7-10, 3.80 ERA) for Tampa Bay. First pitch is set for 1:40 p.m. ET.