Sunderland wing-back Luke O'Nien is likely to be out until the New Year after dislocating his shoulder.
The 26-year-old will have further tests to determine the full extent of the injury, but he is likely to miss an extended period of time.
Top scorer Charlie Wyke is another concern for the managerless Black Cats because of a knee injury and will miss Saturday's visit of Wigan Athletic.
Both players had to go off in Tuesday night's draw against Burton Albion.
Meanwhile, the League One club have appointed Kristjaan Speakman as the club's new sporting director.
The 41-year-old joins the Wearsiders to take on the newly-created role after leaving Birmingham City, where he was academy manager.