Mark McGwire will miss the final three games of the Cardinals’ series in Colorado with back problems. McGwire has left the team to return to St. Louis and receive treatment on his back. The Cardinal slugger missed the opening two games of the season with tightness in his back, and has been uncomfortable since then. He hopes to be ready to go Tuesday when the Cards host San Diego.Cardinal pitchers Jesse Orosco and Mark Thompson have been placed on the disabled list. Orosco has pitched in more games than any other player in major league history, and this is his first trip to the DL. The Cardinals have recalled pitchers Mike James and Justin Brunette to replace Orosco and Thompson.