The Cincinnati Reds placed third baseman Scott Rolen on the 15-day disabled list with a strained left shoulder Saturday. The team brought up infielder Mike Costanzo from Class AAA Louisville.
"He's struggling a little bit," manager Dusty Baker told Cincinnati.com. "He's not feeling real good."
The shoulder has been an ongoing problem for Rolen, who has had four surgeries on it since 2005, including last summer.
Rolen, 37, is hitting .174 with two home runs and 11 RBI this season.
Costanzo, 28, hit .291 with three homers and 11 RBI for Louisville in 23 games.