Kirk Cousins will start in place of Robert Griffin III for the Washington Redskins when they play the Cleveland Browns on Sunday.
"The decision was not my own.... But I will be there for my team!!! In every way I possibly can," Griffin tweeted.
Cousins, a fourth-round pick out of Michigan State, will make his first NFL start at quarterback.
Griffin sprained his right knee late in the fourth quarter of Washington's overtime victory over the Baltimore Ravens last Sunday.
Cousins took over, down eight points with 45 seconds left in regulation, and finished the final two plays and 26 yards of a 14-play, 85-yard touchdown drive. He then rushed for a two-point conversion that sent the game into overtime.
A 64-yard punt return in OT put the Redskins in field-goal range, and Cousins handed the ball off to Alfred Morris twice before Kai Forbath kicked the game-winning 34-yard field goal.