"We will have to sit him down for a while," Yankees manager Joe Girardi said after his team lost to the Minnesota Twins, 6-5, on Wednesday night. "We'll try to get him back after 15 days."
Gardner hurt the elbow while making a sliding catch in the third inning Tuesday night. After the game, he said he slightly injured his wrist, but did not mention the elbow.
Prior to Wednesday's game, he took batting practice and said he felt fine, but after taking more swings in the batting cage about a half-hour before first pitch, the issues returned.
"It wasn't fine," Girardi said. "At some point, in between [batting practice and the cage,] it must have really flared up so we sent him to get an MRI and that is what the diagnosis was."
Girardi didn't know which muscle in the arm was injured, but said it was above the elbow.
Instead of recalling an outfielder to replace Gardner on the roster, the Yankees called up a right-handed reliever, Cody Eppley.
The Yankees' ineffective starting rotation has taxed their bullpen. On Wednesday, Hiroki Kuroda couldn't make it through the fifth inning, causing Girardi to use three relievers.
The Yankees acquired the 26-year-old Eppley off waivers from Texas at the end of spring training. Eppley was 1-1 with an 8.00 ERA in 11 appearances last year for the Rangers.
Gardner was off to a strong start, hitting .321 with a .424 on-base percentage in nine games.