Timothy T Ludwig/Getty Images
San Francisco 49ers star running back Christian McCaffrey suffered a PCL injury and is expected to miss six weeks, head coach Kyle Shanahan told reporters:
The injury is not expected to require surgery, Shanahan said Monday.
Backup Jordan Mason is also set to go on injured reserve with a high-ankle sprain.
McCaffrey went down with a noncontact injury in Sunday night's game against the Buffalo Bills, which was played in snowy conditions. He gave himself up on a run play and appeared to be favoring his right leg.