The Reds needed to make roster moves Tuesday to clear space for Aroldis Chapman and right-hander Aaron Harang, who came off the disabled list to start against the Brewers. They placed outfielder Laynce Nix on the 15-day disabled list, retroactive to Aug. 26, and optioned right-hander Edinson Volquez to Class A Dayton, according to Mark Schmetzer of Reds.com.

Nix has been sidelined since Aug. 25 with a sprained ankle. Volquez had developed some command problems while trying to come back from Tommy John surgery and been moved from the rotation to the bullpen. He hadn’t pitched since Aug. 23, when he logged just two outs while giving up five hits and five runs in an 11-2 loss at San Francisco.

Volquez, a 2008 All-Star in his first season with the Reds after being acquired from Texas for outfielder Josh Hamilton, is scheduled to start for the Dragons on Wednesday, and manager Dusty Baker is hoping he will show enough improvement to start for the Reds on Sept. 6 at Colorado.

“[Pitching coach Bryan Price] made some mechanical changes, and we’d rather have him experiment down there rather than up here,” Baker said. “The guy’s a quality starter, if he can get his stuff together.”