Wainwright will be entering his 15th major league season — all with the Cardinals, tying Bob Forsch for third among pitchers in terms of longevity with the team.
The right-hander went 2-4 with a 4.46 ERA and 40 strikeouts in 2018. He missed nearly four months due to right elbow inflammation.
The three-time All-Star, who has a career record of 148-85 with a 3.32 ERA and 1,623 strikeouts, has finished in the top three of the National League Cy Young voting four times.
He had surgery on his right elbow to remove a cartilage flap last offseason, and he missed the 2011 season after having Tommy John surgery on his pitching arm.