Already thin on cornerback depth, San Francisco 49ers CB Rashard Robinson left the game against the Buffalo Bills during the third quarter. He left the field and headed into the locker room with 49ers personnel. According to multiple sources, Robinson is being evaluated for a concussion.

It was confirmed that Robinson suffered a concussion. He will enter the league mandated concussion protocol this week.

Robinson was replaced by Keith Reaser. The team is already without Jimmie Ward, who opened the season as a starter. In Ward's place, Robinson had been playing at a high level leading up to the game against the Bills. Other than NaVorro Bowman, who is out for the season, Robinson was the 49ers' highest-graded player this season per advanced statistics site Pro Football Focus.