Winn (thumb) is expected to be placed on the injured list Tuesday, Jeff Jones of the Belleville News-Democrat reports.
The 24-year-old shortstop sustained the injury last Tuesday in Cincinnati and attempted to play through it the following day, but he was lifted from that contest and has sat out the past four games. The full extent of the injury has yet to be disclosed after undergoing an MRI and CT scan Sunday, and Winn will now be out until at least the start of September. Nolan Gorman is being called up from Triple-A Memphis to round out St. Louis' roster.