The Redskins have placed cornerback Phillip Buchanon on season-ending injured reserve, the team announced on Saturday.
Taking his place on the roster is cornerback Brandyn Thompson, signed from the practice squad.
Buchanon was listed as questionable for Sunday's game vs. San Francisco with neck and knee injuries.
Buchanon, a 10-year veteran in his second season in Washington, opened the regular season with a four-game NFL suspension.
Once he returned, he played in one game but was slowed by a neck injury suffered in preseason and the knee injury.
Thompson has alternated between the 53-man roster and practice squad this season. He joined the Redskins as a seventh-round draft pick in last April's NFL Draft.
Thompson played in two of the Redskins' seven games this season, seeing action as a reserve cornerback.