PHOENIX — It is a motion St. Louis Cardinals starter Chris Carpenter has made enough in his career to know nothing good usually comes from motioning for the trainer to come out on the field. But what else was he supposed to do in the fourth inning Tuesday?

He couldn’t fire a pitch without significant pain.

“Couldn’t throw,” Carpenter said. “I tried to throw the last one there and it hurt pretty good.”

Carpenter was removed from the game after throwing his warmup pitches for the fourth inning. The righthander was diagnosed at the scene with a strained rib-cage muscle. Carpenter later described it as an oblique injury, pointing to the left side of his torso as he explained that it was still sore after the game. He said he will return to St. Louis and meet with team doctors Thursday.

While the Cardinals wouldn’t confirm their plans to make move Wednesday morning, it is certain that Carpenter is headed to the 15-day disabled list and the Cardinals will be looking for a starter.

“The most important thing is that Chris Carpenter got hurt,” manager Tony La Russa said after his team’s 7-6 loss in extra innings to Arizona. ” No matter what happens in the game, the most important thing is it looks like he’s going to be out for awhile. That kind of overwhelms everything else that happened in the game.”

The Cardinals are operating under a tight turnaround for making a move before Wednesday’s game, which begin at noon Phoenix time. It’s is likely that the Cardinals will make two moves as a result of Carpenter’s injury. The bullpen was taxed covering the seven innings left in the game, and there will be an opening for a starter Sunday at Wrigley Field. The most likely move for the Cardinals is to promote Chris Perez from Class AAA and consider bringing a starter like Mitchell Boggs, who had spot starts in the majors last season, up as well. General manager John Mozeliak declined to name specific options, but he agreed that two moves were possible — one to address the bullpen and the other two solve the starter vacancy.

“That’s a viable option,” Mozeliak said. “The probability of us making a move is there.”

Internally, Kyle McClellan presents the most likely possibility to start in Carpenter’s place.

The Cardinals’ extra-innings loss at Chase Field ended at the final deadline for our Wednesday editions, so it was impossible to get comments from the team in this morning’s paper. One of the benefits of the blog is the ability to relay the information at any time — even after deadline. All of the comments here are from the post-game press access, and they are printed here in addition to the work down for the print edition.

Carpenter said he felt the his torso pinch taking a swing in his at-bat that ended the top of the fourth inning. He went out to the mound to throw his warmup and try to grit through the pain, but it got worse with each throw and eventually kept him from throwing comfortable at all.

“I felt it just a little bit on that swing,” Carpenter said, “and then every warmup pitch it got worse and worse. There’s nothing I can do about it but come out.”

Mozeliak said the team’s experience with this kind of injury dates most recently back to Woody Williams, “and if I recall that was an extended period of time,” the GM said. “In fairness, I think the doctors need to weight in on that.” The “fortunate thing”, according to Carpenter, is that he’s sure it has nothing to do with his elbow — which is twice surgically repaire in the past two years — nor is it anything related to the nerve condition he had in his right shoulder. The strain is on the opposite side of the body.

“It will just take time,” Carpenter said.

Carpenter pitched three scoreless innings, and the Cardinals had just taken a 3-0 lead for him when he went out to begin the fourth inning. Catcher Yadier Molina, whose two-run double was the biggest hit of that rally, was the first to motion for the trainer to come to the field. La Russa knows the length of that walk well, and knows it’s a longer route when you’re worried about what’s waiting for you on the mound. The Cardinals were careful not to take any pitch Carpenter threw in spring training for granted, and they were even hesitant to over-celebrate his debut, during which he took a no-hitter into the seventh inning last week.

This is why.

“You can imagine,” La Russa said. “I’ve talked enough about how important he is.”

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