The 30-year-old left-hander, sidelined for the first three weeks because of biceps tendinitis, attempted to get his 100th regular-season victory on Wednesday night.
Hamels, the 2008 World Series MVP, entered 1-4 with a 9.55 ERA in his last five opening starts.
Philadelphia optioned right-hander B.J. Rosenberg to Triple-A Lehigh Valley. Rosenberg made eight relief appearances, giving up five earned runs and 13 hits in 6 1-3 innings. His only decision came in a 5-4 win against Miami on April 12, when Jimmy Rollins hit a game-ending home run in the 10th.