Rolen was examined on Saturday evening by team medical director Dr. Tim Kremchek. This is the same shoulder that needed surgery multiple times over the years, including last season, when the 37-year-old missed most of the second half.
"If we want to talk about the pink elephant in the room, I've been struggling with it," Rolen told MLB.com before his appointment.
Rolen called head trainer Paul Lessard earlier on Saturday to let him know his shoulder was hurting, and then spoke with manager Dusty Baker after reaching the ballpark. Baker started Todd Frazier in Rolen's place at third base.
"It's not a surgical procedure, where we're going down that road again," Rolen said. "I've had a tough time with it, and I'm in a bad spot right now with it. It's inflammed, fatigued, and it needs to settle down and be rested. I'm not sure if there will be injections or what we'll do with cortisone to try to calm the thing down, but we're going to treat it as well as we can."
In 29 games this season, Rolen is batting .174 with two home runs, 11 RBIs and a .238 on-base percentage. During Spring Training, Rolen looked healthy and played well, as he batted .356, but he has not been able to carry that performance into the regular season.
"It's a tough question, because it's an easy excuse," Rolen said of his shoulder. "I'm responsible for my at-bats when I go out on the field. I have not contributed. I have not been productive in any capacity."
Rolen is in the final year of a contract that is paying him $6.5 million this season.
"I'm not helping anybody right now," Rolen said. "I'm not helping the ballclub right now. I'm probably hurting the ballclub right now, with the way I've been swinging the bat and have been playing."
In a combined 34 games with Louisville and Double-A Pensacola, Costanzo batted .303 with six homers and 24 RBIs. When he appears for the Reds, it will be his big league debut. The 28-year-old was a second-round Draft pick of the Phillies in 2005, and joined Reds in 2010 after playing independent ball for Camden in the Atlantic League.