The Steelers placed Conner (knee) on injured reserve Tuesday, Teresa Varley of the Steelers' official site reports.
Conner underwent surgery earlier in the day to repair the MCL in his right knee, spelling an end to the 22-year-old's rookie campaign. Though he didn't see many snaps behind bell cow Le'Veon Bell this season, Conner generally impressed in spot duty, logging 32 carries for 144 yards (4.5 average) across 14 games. The Steelers signed veteran Stevan Ridley to join Fitzgerald Toussaint in a depth role behind Bell. Conner is expected to be back to full strength for the start of the 2018 season.