Mautz and the Cardinals won't face the Reds on Sunday after the game was postponed due to inclement weather.
The two teams will make up the game as part of a split doubleheader Aug. 17. After being promoted from Triple-A Memphis earlier Sunday, Mautz had been scheduled to start the series finale in Cincinnati. As a result of the postponement, the Cardinals no longer have a need for a temporary sixth starter, so Mautz could be optioned back to Memphis before making his MLB debut.