Rusch started in place of Clement last Sunday while the right-hander nursed a bad shoulder, and suffered an 11-1 home loss to the Marlins in his shortest start of the season.
The left-hander gave up four runs, seven hits and two walks in 3 1-3 innings. It was his 13th start of the season and first since Aug. 20.
“I really struggled command-wise,” Rusch said. “They were putting pressure on me from the beginning.”
Rusch is 3-0 with a 3.88 ERA in 11 road games this season, including six starts.
The Cubs lost 6-5 on Saturday, missing an opportunity to gain ground on the NL wild card-leading San Francisco Giants, who dropped a 5-1 decision to San Diego.
Alou is batting .400 (12-for-30) with four homers, eight RBIs and eight walks over his last nine games.
The Reds snapped a three-game slide behind Wily Mo Pena, who hit two homers and drove in three runs Saturday. Pena, who finished 2-for-4, has four homers and nine RBIs in his last nine games.