Although the club did not divulge terms of the deal, the NFL Network's Ian Rapoport reported that the contract is worth "up to $7 million" with "void and buyback provisions" that would allow the team or McCoy to walk away from the deal with little to no risk.
"Why? Cause Colt's a great player to have here," Washington head coach Jay Gruden told reporters Friday. "He's a great backup quarterback, he's a great quarterback in general and if something happens to Alex (Smith) -- knock on wood -- I know that our team is in good hands and that position, you don't want to mess around with."
The Redskins have a new starter this season in Smith, who was acquired in an offseason trade with Kansas City. He replaces Kirk Cousins, who signed with the Minnesota Vikings as a free agent.
McCoy has been Washington's backup quarterback since 2014.
For his career, McCoy has a 60.3 completion percentage for 5,586 yards, 25 touchdowns, 23 interceptions and a 78.9 quarterback rating. He was drafted in 2010 by the Cleveland Browns, where he played three seasons before playing one season for the San Francisco 49ers prior to joining the Redskins.