Washington Redskins quarterback Case Keenum left Thursday night's game against the Minnesota Vikings to be evaluated for a head injury, the team announced.
He was quickly ruled out after being diagnosed with a concussion.
Rookie first-round quarterback Dwayne Haskins started the second half in Keenum's place.
Prior to the injury, Keenum had thrown for 130 yards and zero touchdowns or interceptions on 12-of-16 passing.
On the heels of getting traded to Washington from the Denver Broncos during the offseason, Keenum had registered 1,1213 yards, nine touchdowns and four picks across six starts entering Thursday's contest.