Leahy will have his start pushed back after Friday's contest against the Reds was postponed due to inclement weather.
The game will be made up as part of a doubleheader Saturday, and Leahy will draw a start in one of those tilts. He's collected a 3.94 ERA, 1.55 WHIP and 34:20 K:BB through 45.2 innings this season in his transition into the Cardinals' rotation.