The St. Louis Cardinals faithful had a surprise at Busch Stadium on Opening Day.

Adam Wainwright didn't get the start to begin his 19th MLB season (he's dealing with a groin injury), but he did give the performance of a lifetime – on the microphone.

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Wainwright national anthem

ST. LOUIS, MO - MARCH 30: Adam Wainwright #50 of the St. Louis Cardinals sings the national anthem prior to the game between the Toronto Blue Jays and the St. Louis Cardinals at Busch Stadium on Thursday, March 30, 2023 in St. Louis, Missouri. (Dilip Vishwanat/MLB Photos via Getty Images)

Yes, the three-time All-Star surprised everyone in attendance when he was called upon to sing the national anthem.

The public address announcer said an "up-and-coming singer" from St. Louis was taking the mic, and the crowd went nuts when they realized it was their beloved starter.

Wainwright had a chance to walk off into the sunset with Albert Pujols and Yadier Molina after last season, but he opted to stay for one more season – and why wouldn't he? He pitched to a 3.71 ERA in 32 starts last season.

Adam Wainwright #50 of the St. Louis Cardinals pitches against the Atlanta Braves in the first inning at Busch Stadium on August 28, 2022 in St Louis, Missouri.

Adam Wainwright #50 of the St. Louis Cardinals pitches against the Atlanta Braves in the first inning at Busch Stadium on August 28, 2022 in St Louis, Missouri. (Joe Puetz/Getty Images)

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Wainwright came up as a reliever and was the closer for the 2006 World Series championship team. The following season, he joined the rotation full time, and has given himself quite the resume.

The 41-year-old owns a career 3.38 ERA and was a finalist for the Cy Young Award in 2009, 2010, 2013 and 2014. He also finished in seventh place in 2021, his age-39 season.

Busch Stadium on Opening Day

A general view of Busch Stadium prior to a game between the St. Louis Cardinals and the Toronto Blue Jays on Opening Day on March 30, 2023 in St Louis, Missouri. (Joe Puetz/Getty Images)

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Wainwright's Cardinals are the favorites to defend the National League Central title – he recently played for Team USA in the World Baseball Classic.