He pitched a scoreless fourth inning for Triple-A Scranton/Wilkes-Barre on Sunday at Rochester and sustained the injury while warming up for a second inning. Recovery time for Tommy John surgery is generally 12-18 months.
The injury follows one to right-hander Bryan Mitchell in his final Spring Training appearance. Mitchell sustained a fractured left big toe while covering first base that required surgery, putting him out until at least August.
Rumbelow was a seventh-round selection by the Yankees in the 2013 Draft from Louisiana State University. He allowed five runs and 15 hits in 8 2/3 spring innings (5.