Now, he's ready to pick up the slack with ace Chris Carpenter sidelined indefinitely.
Wainwright pitched five shutout innings and the Cardinals beat Miami 2-1 on Friday, overcoming Jose Reyes' first home run for the Marlins.
Wainwright, who missed the Cardinals' championship run last year following Tommy John surgery, allowed three hits and struck out five. He has given up just an unearned run in 14 innings this spring.
''If you look at our staff as a whole, we'll do a big job as a whole picking Carp up. He has done that for years. Time to return the favor,'' Wainwright said.
The Cardinals announced Friday that Carpenter has nerve irritation that has led to weakness in his pitching shoulder. There is no timetable yet for his return to the mound.
Carpenter, a three-time All-Star, was evaluated in St. Louis this week. The team said there is no new nerve injury and the cervical disc injury that occurred earlier in spring training is a ''non-issue.''
The 2005 NL Cy Young Award winner is expected back in camp by Monday.
Carpenter, who turns 37 next month, pitched the Cardinals to World Series championships in 2006 and 2011. The right-hander was 11-9 with a 3.45 ERA last year, leading the NL in innings (237 1-3) and starts (34). He threw 36 more innings in the postseason, going 4-0 with a 3.25 ERA in six starts.
Marlins starter Carlos Zambrano looked rusty, allowing two runs and five hits, including three doubles, in 4 1-3 innings. He walked four and struck out one.
''He struggled a little bit. It wasn't pretty, but he got it done. That's all I care about, to make sure he's healthy,'' Marlins manager Ozzie Guillen said.
Zambrano threw 82 pitches, 47 for strikes.
Reyes hit a solo shot in the eighth off Kyle McClellan, his first homer since leaving the New York Mets to sign a $106 million, six-year contract with the Marlins in the offseason.
The loss left the Marlins 0-6 with two ties in their last eight games. They have totaled 17 runs during that stretch and haven't won since March 15.
Miami still hasn't played its projected opening-day lineup because of knee injuries to left fielder Logan Morrison and right fielder Giancarlo Stanton. Both are still hoping to be ready when the season starts April 4.
Reserve infielder Greg Dobbs also hasn't played because of a strained left hamstring.
''You have three guys not in the lineup who should be on it, that's kind of hard. But meanwhile, we're going to hit. We're going to be fine. I don't worry about that,'' Guillen said.
''We're playing good. I'm happy. When I'm not happy with the way we play, I will let you guys know and I will let them know, too. That's easy for me.''
Wainwright, who won 39 games from 2009-10, has faced the Marlins in his last two starts. He allowed one unearned run in four innings Sunday and is in line to face them again in his next start.
''Any time you get him out, you've done a good job,'' Wainwright said. ''It's good to get in those kinds of situations in spring training. ... There were some quality pitches that allowed me to get me out of that inning.''
Wainwright's 2011 season ended in spring training when the team announced he would have elbow ligament replacement surgery. Now he's in line to start St. Louis' home opener April 13 when the team will raise its championship banner at Busch Stadium.
''I haven't thought about it all,'' Wainwright said. ''I know it will be very special and very cool, but I've still got some work to do down here.''
Zambrano, in line to start the Marlins' fourth game, has a 4.63 ERA in four starts.
''The stuff wasn't there but I was able to get people out. I'm ready for the season,'' he said. ''There are things I have to correct during the season and I will make the adjustment.''
Koyie Hill scored the Cardinals' second run. He ran home from third when Cora was caught trying to steal second.
NOTES: Marlins OF Scott Cousins was reassigned to minor league camp. He was batting .147 in 13 games. ... Miami LHP Wade LeBlanc, competing for a bullpen spot, will start Saturday against LHP Felix Doubrant and the Boston Red Sox. RHP Anibal Sanchez will pitch in a minor league game Saturday on a back field.
Link to boxscore: St. Louis 2, Miami 1