Montgomery will pitch in a simulated game on a back field Thursday, John Denton of MLB.com reports.
Montgomery has struggled to begin spring training, allowing six earned runs on eight hits and a walk with six strikeouts over seven innings. Despite the early issues, the southpaw is in no danger of falling out of the Cardinals' rotation. He's on a one-year, $10 million contract this season, and he figures to slot in behind Jack Flaherty at the top end of the rotation.