Cole Hamels will no longer be starting Friday night against the St. Louis Cardinals as originally scheduled.
Instead, former Phillies reliever Phillippe Aumont, who has been transitioned to a starter in the minors, will face Cardinals lefty Tyler Lyons.
The Phillies announced shortly before Thursday's game that Hamels was scratched due to a mild right hamstring strain.
This season Hamels is 5-5 with a 2.96 ERA in 14 starts. His 94 1/3 innings leads all pitchers in the National League.
With Triple-A Lehigh Valley this year, Aumont went 3-4 while compiling a 2.35 ERA in 14 games, 10 of which were starts.