McGwire, who recently admitted to using performance-enhancing substances for most of his playing career and joined Bob Costas for an exclusive interview on MLB Network on Monday, will be on stage at a hotel near Busch Stadium and will speak with the media at about 1 p.m. CT.
Earlier this week, McGwire ended more than a decade of speculation by acknowledging he used steroids during his career, including during his record-breaking 70-homer season in 1998.
The 46-year-old has made the media rounds recently, speaking to various outlets about his use of PEDs but maintaining that he only used them in low doses to recover from injury, adding that he does not believe they enhanced his level of play.
The 2010 Warm-Up will be held at the downtown Hyatt Regency St. Louis at the Arch, which will hold several of the Cardinals' big-name players, including Matt Holliday and Albert Pujols. The event is held 9 a.m. to 5 p.m. on Saturday and Sunday, then 9 a.m. to 3 p.m. on Monday, Martin Luther King Jr. Day.
Cardinals pitchers and catchers are scheduled to report to Spring Training in Jupiter, Fla., on Feb. 18.
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.