Fleming is slated to start Sunday's game against the Rockies at Coors Field, Kevin Gorman of TribLive.com reports.
Fleming was called up from Triple-A Indianapolis on Friday but went unused out of the bullpen for the first two games of the Pirates' series in Colorado. He'll step into the rotation for the series finale Sunday as Pittsburgh looks to give each of their other starters an additional day of rest, but Fleming will likely head to the bullpen or return to Triple-A immediately after the start. Fleming had worked as a multi-inning reliever for Indianapolis prior to his call-up, covering at least two frames in each of his last four appearances while pitching to a 5.68 ERA and 1.15 WHIP in seven outings overall.