Updated

The Washington Redskins on Saturday ruled out quarterback Robert Griffin III for Sunday's contest against the Cleveland Browns.

Redskins coach Mike Shanahan announced on Thursday Griffin would be a game- time decision, but the team's website announced on Saturday the second-overall selection will not play.

Griffin confirmed the story on his Twitter account stating, "The decision was not my own... But I will be there for my team!!! In every way possible I can."

Griffin, who suffered a Grade I sprain of the lateral collateral ligament in his right knee during the fourth quarter of Sunday's 31-28 overtime triumph over the Ravens, has started every game this season for Washington and has led the team back into playoff contention with a four-game win streak.

The Redskins now sit at 7-6 and trail the New York Giants by a game for the top spot in the NFC East.

The 2011 Heisman Trophy recipient has been particularly good during the Redskins' current unbeaten run, having amassed 10 touchdown passes and only one interception along with a 68.5 percent completion rate over that stretch.

Fellow rookie Kirk Cousins will make his first career start in Griffin's place. The fourth-round pick took over for a hobbled Griffin against the Ravens and threw a touchdown pass to Pierre Garcon with 29 seconds left in regulation to bring the Redskins within 28-26, then ran in the subsequent conversion attempt to force overtime.

Cousins has completed 7-of-11 passes for 137 yards with two touchdowns and a pair of interceptions in two games this season.