ST. LOUIS -- For the last month, Scott Rolen has been battling to get his injured left shoulder back into shape, hoping and praying he could return for a postseason run at a World Series title with the Cardinals.

But every time Rolen seemingly made progress, it was followed by regression twice as significant. In the end, the All-Star third baseman realized he only had one choice.

On Sunday afternoon, Rolen announced he would undergo season-ending surgery to repair the torn labrum in his left shoulder that has caused him problems ever since he injured it on May 10 when he collided with Dodgers first baseman Hee-Sop Choi.

"I really didn't have a decision," Rolen said. "I know my body. I know my shoulder. Timing was the issue. This is my only choice right now, to get the procedure done. I don't have a chance to rehab it and come back. I wish there was a choice to rehab it and come back to compete, but that's not a choice."

The date of the surgery has not been set, but Rolen says it will likely take place in the next week to 10 days. The Cardinals will be on the road until Sept. 5. Cardinals team physician Dr. George Paletta and Reds team physician Dr. Timothy Kremchek will perform the surgery together. Rolen said he expects to be back, playing at 100 percent, by Spring Training.

"My understanding is that I should have no trouble getting back for Spring Training," Rolen said. "It's a six-month rehab, maybe, and I have a little extra time in there. Hopefully, I should have no trouble coming back from the first day on."

On Thursday, Rolen announced that he had gotten a second opinion on his shoulder from Kremchek, who advised him to have surgery.

"One of the questions is, What's my best chance to win a ring as a St. Louis Cardinal?" Rolen said on Thursday. "It might be not to play. That's not easy. That's not an easy decision, to say I can't help this team. I can hurt this team, but I can't help this team. So my best shot of helping this team win a World Series is to not play. That's not an easy decision to make."

Rolen had surgery earlier this year to repair the shoulder, but never made a successful comeback. His announcement that he received a second opinion has caused some speculation as to the accuracy of Paletta's initial diagnosis. Rolen and Cardinals manager Tony La Russa have been quick to snuff any such speculation.

"Whether it was Scott or any other member of our organization, everything that could have been done has been done," La Russa said.

"I said earlier that Dr. Paletta gave me the best shot of coming back, rehabbing it and coming back," Rolen said. "I thank him for that. I don't look at Dr. Paletta and his medical decisions at all, and question it."

Rolen played in 56 games this season, batting .235 with five home runs and 28 RBIs.

"I did my rehab, worked as hard as I could and didn't cut any corners, and I was worse in the end than I was in the beginning," Rolen said. "So, it wasn't a question of, 'Can I do rehab and come back?' I did the rehab, gave it my best shot and it didn't work. There is no rehab for me. The question was, 'Can I get away without surgery?' The answer was, 'No' from Dr. Paletta and Dr. Kremchek."