Chicago Cubs reliever Matt Guerrier underwent surgery to repair the flexor mass in his right arm on Friday.
He is expected to miss six to eight months.
The 35-year-old right-hander last pitched on August 7 and was placed on the 60-day disabled list two days later.
Acquired from the Dodgers in the Carlos Marmol trade on July 2, Guerrier went 2-1 with a 2.13 ERA in 15 games for the Cubs. For the year, he is 4-4 with a 4.01 ERA in 49 appearances.
Guerrier's three-year, $12 million contract expires after this season. Over 528 career games with the Twins (2004-10), Dodgers (2011-13) and Cubs, he is 27-34 with a 3.51 ERA and six saves.