Phelps left Sunday's start against the Boston Red Sox after only two innings. He gave up five runs on six hits and threw 53 pitches.
After the game, manager Joe Girardi told reporters that Phelps had been dealing with elbow problems with three or four weeks.
Phelps has been used this season as both a starter and a reliever. In 108 1/3 innings he has an ERA of 4.24 and a WHIP of 1.394.
Phelps will be the fifth Yankees starter currently on the DL, joining C.C. Sabathia, Masahiro Tanaka, Ivan Nova and Michael Pineda.
The Yankees called up reliever Matt Daley to take Phelps' spot on the roster. This will be Daley's third stint in the majors this season. He has not pitched for the Yankees since June 7. He has a 4.85 ERA in 13 major-league innings and a 3.63 ERA in 34 2/3 innings at Triple A Scranton-Wilkes Barre this season.
- Dan Gartland