Conner will undergo knee surgery Tuesday and will be placed on injured reserve, Aditi Kinkhabwala of NFL Network reports.
Conner played a career-high nine snaps in Sunday's loss to the Patriots, but he also suffered a knee injury in the contest, a setback that will cut short his rookie season. Fellow running back Le'Veon Bell has taken 92 percent of the snaps in the Steelers' backfield this season, so the loss of Conner won't have a major effect on the offense. Fitzgerald Toussaint seems likely to take over as Pittsburgh's No. 2 back, and head coach Mike Tomlin indicated the team would add another running back to the roster in Conner's place.