Conner was removed from Thursday's game against the Browns to be evaluated for a shoulder injury.
The 24-year-old missed the previous two games with an AC joint sprain in his right shoulder but practiced fully this week, though he appears to have aggravated the injury during the first half Thursday. Conner was initially questionable to return but has since been ruled out. Jaylen Samuels and Trey Edmunds should handle backfield work for the Steelers in his absence.