Garrett was diagnosed with a partial tear of the ulnar collateral ligament in his left elbow, Andre Fernandez of the Miami Herald reports.
This is tough news for both parties, as Garrett was one of the few bright spots in the Marlins' farm system. He was 1-0 with a 2.93 ERA and 16:6 K:BB through 15.1 innings pitched (four starts) with Low-A Greensboro this season. Garrett will explore other options before deciding whether he'll undergo Tommy John surgery, but he'll be sidelined for an extended period of time either way.