Hamels, 30, battled shoulder inflammation all through spring training and had to start the regular season on the 15-day DL. He also missed time with minor shoulder problems in 2006 and 2011.
In three minor league rehab starts with the team's High Class-A affiliate, Hamels had a 2.12 ERA with 12 strikeouts and one walk in 17 innings. He allowed one run in seven innings on Thursday.
Hamels went 8-14 with a 3.60 ERA (106 ERA+) in 33 starts and 220 innings last season. It was his fourth straight year over 200 innings. Hamels is 99-74 with a 3.54 ERA in parts of eight MLB seasons.
The Phillies will be in Los Angeles for a four-game series against the Dodgers from next Monday through Thursday.