Carpenter threw on flat ground Friday and in a bullpen session Saturday. Both went well, but when the right-hander arrived at Minute Maid Park on Sunday, he went to La Russa and informed the manager of discomfort in his elbow.
"He had a little bit of swelling, not a lot," La Russa said. "So [he's] going to Dr. [George] Paletta before we make any decision, but right now, there's no chance he'll pitch Tuesday."
Carpenter left for St. Louis to see Paletta while the team heads on to Pittsburgh to begin a three-game series against the Pirates on Monday afternoon. It was uncertain following Sunday's game whether this latest setback would necessitate a trip to the disabled list for the former National League Cy Young Award winner.
La Russa said he wanted to confer with Paletta before proceeding further.
"We're always going to be real careful with him, we just got excited [Saturday] because he threw the ball so well in the 'pen," La Russa said. "But he didn't back off, he really wanted to test it and he came in [Sunday] and said he's got some discomfort."
Carpenter also had some discomfort following his Opening Day start against the Mets, which caused the team to skip his next scheduled start. He was supposed to be back in the rotation on Tuesday.
"[There's] just enough [swelling] this time that he's not going to pitch Tuesday," La Russa said. "I don't want to say anything more until we compare notes, but I know he's not pitching Tuesday."
La Russa said Tuesday's starter will be announced later.
"[St. Louis general manager] Walt [Jocketty] and I talked a little bit," La Russa said. "We said we'd discuss it further."
The Cardinals are hoping for the best for the ace, but are preparing for all scenarios.
"Obviously you don't want you No. 1 guy [out]," Cardinals first baseman Albert Pujols said. "We have to deal with it, we have to survive. We deal with injuries in the past. This is not the first time this is going to happen that somebody is hurt. Right now, we're dealing with our right fielder [Juan Encarnacion on the disabled list], last year myself. Hopefully this is something that's not too serious. He's the guy who gets everbody going."
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.