The Cubs are opting to forego Donn Roach's spot in the rotation and will trot out newly-acquired Clayton Richard against the Marlins Saturday instead.
Richard was sent from the Pittsburgh Pirates to the Cubs Friday for cash considerations.
The 31-year-old lefty is 4-2 with a 2.09 ERA and 1.179 WHIP in nine starts for Pittsburgh's Triple-A affiliate in Indianapolis.
Richard - who was ranked as the No. 3 prospect in the White Sox system before the 2008 season - was involved in one of the more high-profile trades in recent Chicago baseball history when he was sent to the San Diego Padres as part of the deal that brought Jake Peavy to the South Side.