Playing without former MVP Joey Votto, the Reds dropped the series opener with the Arizona Diamondbacks at Great American Ball Park.
Pitching his first game in 10 days, Bronson Arroyo gave up five earned runs in three innings pitched and fell to 4-6.
Todd Frazier started at first base and hit in Votto's customary three hole in the Reds line-up. Drew Stubbs also moved to the lead-off slot and drove in two runs.
It snaps the Reds six game win streak. Johnny Cueto will pitch Tuesday night after being skipped in the rotation Sunday due to a blister.