The Diamondbacks will option Bratt to Triple-A Reno prior to Thursday's game in St. Louis, Nick Piecoro of the Arizona Republic reports.
Bratt had a solid abbreviated major-league debut Wednesday versus the Cardinals, yielding one run over three innings of work. The left-hander is not fully stretched out yet after recently returning from injury at Reno, so he will continue to rebuild his stamina at the team's top minor-league affiliate. Brandon Pfaadt will enter the Arizona rotation in Bratt's place.