Marsh is scheduled to start Saturday's game against the Twins in Kansas City.
He'll be making his second straight turn through the rotation as a replacement for Michael Lorenzen (hamstring), who was placed on the injured list Aug. 28. Through 22 appearances (21 starts) for the Royals this season, Marsh has gone 7-8 with a 4.70 ERA, 1.24 WHIP and 100:34 K:BB in 111 innings.