Former Red Sox Prospect Struggles In Minor-League Rehab Assignment

Former Boston Red Sox prospect Michael Kopech is on the comeback trail … again.

Los Angeles Dodgers manager David Roberts said Wednesday that Kopech is beginning a minor-league rehab assignment, according to The Athletic’s Fabian Ardaya.

The right-hander took the mound Thursday for Triple-A Oklahoma City, and it didn’t go well. Entering the game in the fourth inning, he gave up three runs on two hits and two walks in 2/3 of an inning pitched.

Kopech ended up taking the loss for the Comets. He threw 24 pitches, but just 10 for strikes as the Albuquerque Isotopes beat Oklahoma City, 8-5.

The 29-year-old started the 2025 season on the injured list with a shoulder injury and returned from the 60-day IL in June. He looked sharp, making eight scoreless relief appearances. That included eight strikeouts in seven innings of work.

“(B)ut something was clearly off in his final appearance, as he walked three of the four batters he faced before being lifted and placed on the injured list to inflammation in his knee,” MLB Trade Rumors’ Steve Adams wrote Thursday.

“Kopech initially downplayed the severity, but once the inflammation subsided, imaging revealed a torn meniscus,” Adams added. “He underwent surgery and was quickly transferred back to the 60-day IL. He’s been on the injured list since July 1, so Kopech isn’t eligible to be activated until the very end of the month.

“It’s encouraging that he’s already setting out on a rehab stint, as he’ll have a runway of more than two weeks to build up before he’s first eligible to return,” Adams concluded.

The Red Sox selected Kopech in the first round of the 2014 MLB Draft and he quickly became one of the club’s top prospects.

Kopech impressed in the minors, reaching High-A Salem in 2016, where he went 4-1 with a 2.25 ERA in 11 starts.

That caught the attention of the Chicago White Sox, who acquired him in the blockbuster 2016 trade that sent left-hander Chris Sale to Boston.

Chicago traded Kopech to the Dodgers in 2024 as part of a three-team deal with the St. Louis Cardinals. He then helped Los Angeles win its second World Series title in five seasons.

Kopech is 21-33 with 15 saves and a 4.11 ERA in 178 appearances over six MLB seasons.