Yankees LHP Jordan Montgomery underwent Tommy John surgery on his left elbow on Thursday at New York-Presbyterian Hospital, the team announced.
A UCL tear consistent with Montgomery's MRI was found, and reconstruction was performed as planned. A loose bone chip was also removed from Montgomery's left elbow.
Montgomery's Tommy John surgery weakened th Yankees' already-thin starting rotation depth.
Domingo German has been in the Yankees' rotation in German's place, with Luis Severino, Masahiro Tanaka, Sonny Gray, and CC Sabathia taking up the other four spots.
Montgomery, 25, had a 3.62 ERA (4.18 FIP) and 1.35 WHIP with 23 strikeouts in 27.1 innings (six starts) this season.