Culliver, 26, was a third-round pick by the San Francisco 49ers in 2011 and played his first four seasons with the team. Last season, he had four interceptions, 45 combined tackles and one forced fumble.
In 46 career games with the 49ers, Culliver had seven interceptions. He missed the entire 2013 season with a torn ACL.
Washington finished No. 20 in yards allowed and No. 29 in scoring defense last season. The Redskins fired defensive coordinator Jim Haslett and hired San Diego Chargers linebackers coach Joe Barry to replace him.
- Paul Palladino