Reds first baseman Joey Votto has had surgery to repair torn cartilage in his left knee, leaving him sidelined for three to four weeks.
An MRI on Monday evening found the tear. Votto hurt the knee June 29 while sliding into a base. The knee had gotten better but began to bother him again, prompting the test.
The Reds will have to try to stay in first place in the NL Central without their top hitter. Votto is batting .342 and leads the National League in doubles, walks, on-base percentage and extra-base hits.
The Reds replaced him on the roster Tuesday by calling up right-handed starter Todd Redmond from Triple-A Louisville. Cincinnati got Redmond from Atlanta on Saturday for shortstop Paul Janish in a swap of minor leaguers.