McCoy injured his neck in Washington's Week 14 shutout loss to the St. Louis Rams. He was cleared to play against the New York Giants this past Sunday but reinjured himself in the first quarter and was replaced by Griffin.
McCoy was reportedly dealing with a herniated disc in his neck.
McCoy, originally the team's third-string quarterback, replaced an ineffective Kirk Cousins in Week 7 against the Tennessee Titans and earned his first start of the season against the Dallas Cowboys the following week. Griffin returned from an ankle injury in Week 9 and started three games before losing the job to McCoy.
Gruden was critical of Griffin's play in Washington's loss to the Tampa Bay Buccaneers last month, saying Griffin "had some fundamental flaws." He later apologized. There were conflicting reports earlier this month about whether Gruden believes Griffin is a long-term solution at quarterback.
Griffin completed 18 of 27 passes for 236 yards and a touchdown after replacing McCoy on Sunday.
Washington is 3-11 and has lost its last six games. The team was 3-13 in 2013 and has never had consecutive three-win seasons in franchise history.
- Dan Gartland