The San Francisco 49ers lead the New Orleans Saints 42-40 late in the fourth quarter at the Mercedes-Benz Superdome but haven't escaped the injury bug just yet. The latest casualty appears to be cornerback K'Waun Williams, who walked off the field with team doctors and was replaced by Emmanuel Moseley.

Williams was shaken up after a tackle on running back Alvin Kamara and is being evaluated for a head injury.

Williams is in his fifth NFL season and his third with San Francisco. He has played in all 13 games with the 49ers this season.

San Francisco is already without veteran pass rusher Dee Ford (hamstring) and starting center Weston Richburg (knee, ankle).