The news broke during a game on Sunday night at Wrigley Field that Wainwright started against the Cubs, which was the reason he opted out. All-Star pitchers who made starts on Sunday were given the option of pitching a maximum of one inning or declining the chance and letting somebody else play.
Mujica, who earned the closer role this season, is 2-1 with a 2.20 ERA and 26 saves. In Sunday's 10-6 win over the Cubs, he came on in the eighth and allowed a pair of inherited runners to score and tie the game, resulting in just his second blown save all season. But after the Cards scored four times in the ninth, Mujica retired the Cubs in order for the victory.
Back in Spring Training, the Cardinals were looking for somebody to solidify the closer's role and take charge offensively as the team's leadoff hitter. Mujica earned the ninth-inning duties, while Matt Carpenter emerged as a mainstay atop the batting order.
Both are now on the NL All-Star roster.
"No question, we were searching [for a closer] at the beginning of the year, and there were times when we were struggling," manager Mike Matheny said. "The closer role is very different. You can play the hot hand, I believe, probably more in that leadoff role. I think you'd be able to get by with that, more so or more easily than closer-by-committee. That's tough to do."
Prior to Mujica joining the NL roster in place of Wainwright, the Cardinals had five All-Stars -- including catcher Yadier Molina and right fielder Carlos Beltran, who were voted in by fans as starters.
Brian Hedger is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.