The Reds optioned Moll to Triple-A Louisville on Monday, Mark Sheldon of MLB.com reports.
Moll had made five scoreless appearances after coming off the injured list April 23, but he nonetheless now finds himself without a spot on the 26-man active roster. The Reds will make a corresponding move prior to Tuesday's game, with Frankie Montas (forearm) presumably on track to be activated from the 15-day injured list ahead of his start that day versus the Diamondbacks.