The NFL announced Friday that RB Jahid Best will be out for Sunday’s game at Buffalo against the Bills.
The 49ers announced that RB Chris Polk will start in his place.
It’s not known if Polk or Polk will play, though.
Best has been a steady presence for the 49ers, averaging 7.7 yards per carry in his three games since Week 6.
The two-time Pro Bowler has also scored a touchdown on two carries in those games.
Best was inactive in Week 3 at New Orleans and Week 4 vs. Oakland.
The NFL has also been mum on RB Rashad Jennings, who was placed on IR and is unlikely to play in Week 5 vs. the Lions.