Wainwright, 29, will undergo Tommy John surgery to replace the ulnar collateral ligament in his right elbow. The typical recovery time for a starting pitcher who undergoes the operation is roughly 12-15 months.
The club had expected that Wainwright would need the surgery after the pitcher consulted with Dr. George Paletta, the team's head physician, on Wednesday. A second opinion from Dr. Lewis Yocum confirmed Paletta's findings. Yocum notified Mozeliak of his opinion on Wednesday evening.
"It's not a real surprise to us this morning," Mozeliak said, "but certainly a disappointment and a finality to this process."
A date for the surgery has not been determined, but Paletta will perform the operation.
Mozeliak, who solemnly announced Wainwright's absence and the reason for it on Wednesday morning, spoke at about 5:45 p.m. ET on Wednesday and didn't back off from what he said in the morning. When Tommy John surgery was mentioned as a possibility, Mozeliak said, "When you have ligament damage, that's what it usually results in."
Three members of Cardinals' projected 2011 rotation -- Chris Carpenter, Jake Westbrook and Jaime Garcia -- have undergone the procedure. And the fifth member, Kyle Lohse, underwent surgery on his forearm last year because of a compressed nerve.
Although pitchers now routinely recover from the procedure without long-term effects, Wainwright, 29, is certain to miss the entire 2011 season when the surgery is performed.
When Wainwright does go under the knife, his 2012 and '13 options -- totaling $21 million -- won't automatically vest.
As part of a four-year, $15 million contract signed in March 2008, Wainwright's contract included a $9 million club option for 2012 and a $12 million club option for '13. But because he finished in the top five in National League Cy Young Award voting each of the last two years -- he needed to only once -- all he needed was to not finish the 2011 season on the disabled list to trigger both salaries.
When Wainwright does undergo surgery, his future with the club becomes uncertain.
Wainwright was throwing batting practice on Monday when, on the third-to-last pitch, he experienced a sensation in his right elbow. He later developed significant stiffness in the elbow and was examined. "Based on the initial evaluation from our training staff, things do not look encouraging," Mozeliak said Wednesday morning.
The general manager suggested the latest episode was linked to earlier ones. Wainwright experienced elbow problems in 2004, the year before he made his big league debut and in 1998, two years before the Braves used the 29th selection in the First-Year Player Draft to make Wainwright a professional. But Mozeliak indicated that the club's sense of this specific injury is a new one.
The St. Louis Post-Dispatch reported early Wednesday that Wainwright's elbow had been examined in November and that the pitcher was told the joint was stable. The newspaper quoted him on Feb. 10, saying "My ligament is intact and strong. It's not like it's ready to pop."
The loss of Wainwright will be a most significant blow to the Cardinals, who were identified by some as favorites to win the National League Central. La Russa characterized his absence as "huge loss" and made no effort to diminish the projected impact. "It's not a good day," he said.
Wainwright was the Cardinals' most effective and successful starting pitcher in 2010, placing second to Roy Halladay in the balloting for the National League Cy Young Award after finishing third in 2009. He won 20 games last season and produced a 2.42 ERA in 33 starts and 230 1/3 innings. He had won 19 games the previous season.
He has pitched more than 200 innings in three of his four big league seasons. When he pitched 132 innings in 2008, the problem was unrelated to his right elbow; it was a finger ligament that disabled him them.
Mozeliak identified that 2004 problem as a strained ligament. He said Wainwright had experienced no recurrence of the problem until last summer when he pitched against the Cubs on Sept. 14. He made two subsequent starts, pitching eight and six innings but ended his season Sept. 24, though he could have made one more.
La Russa declined to identify the pitcher most likely to fill the void in the rotation. He indicated that not only did no need exist for an immediate decision, but that the decision needn't be made until the final days of Spring Training.
Nonetheless, five pitchers, three of them not on the Cardinals' 40-player roster, are seen as the most likely candidates -- veterans Miguel Batista, Ian Snell and P.J. Walters, Lance Lynn and Kyle McClellan. Each is right-handed; Walters and McClellan are on the roster. Lynn is the only one without big league experience, Batista is 40, and Snell, who has a 38-53 record after seven seasons with losing teams, is a one-time Opening Day starter, albeit with the pitching-poor Pirates in 2008.
La Russa indicated the replacement part would come from the organization and Mozeliak didn't contradict the manager but left open the possibility of bringing in a starter late in camp in the unlikely event a good one became available.
Cardinals pitching coach Dave Duncan is renowned for "fixing" veteran pitchers and revitalizing careers, but McClellan appears to be the favorite. He has prepared as a starter for each of the last two seasons but has pitched exclusively in relief. He has a 7-15 record and 3.23 ERA in 202 big league appearances and 217 2/3 innings.
Matthew Leach is a reporter for MLB.com. Read his blog, Obviously, You're Not a Golfer and follow him on Twitter at @MatthewHLeach. Marty Noble is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.