The right-hander was placed on the 15-day disabled list before Sunday's game against the Milwaukee Brewers. Philadelphia called up right-hander Luis Garcia from Triple-A Lehigh Valley to replace Morton.
He got hurt in the second inning of a 10-6 win Saturday night in Milwaukee while running to first on a sacrifice attempt. Morton said he had felt a "pop" in his hamstring.
Morton is 1-1 with a 4.15 ERA in four starts.
Garcia was 0-1 with a 4.26 ERA in five games in the minors.