The move was announced on Wednesday after the 24-year-old underwent MRIs to reveal the injury. He was hitting just .179 with four home runs and 10 RBIs, and has struck out in half of his 84 at-bats.
The team added a key part after losing Judge, signing free agent Billy Butler to a deal. They wasted little time getting him on to the field, as he was in the starting lineup for Thursday's series opener with the Red Sox.
The 30-year-old was released by the Athletics following a scuffle with teammate, Danny Valencia, during batting practice in August. Butler was placed on the DL with a concussion, which he suffered in the fight.
In 85 games with the A's, he hit .276 with four home runs and 31 RBIs. His lone All-Star season came in 2012 with the Kansas City Royals. The now clean-shaven Butler does add a veteran presence for New York, much of which was lost at the trade deadline. He is expected to get plenty of playing time down the stretch, as he also adds more punch in the middle of the playoff-hopeful Yankee lineup.