McCoy's return means the Redskins have the same quarterback situation as they did last season.
Robert Griffin III was named the starter by coach Jay Gruden, but he does not have a stronghold on the position. Kirk Cousins remains under contract, and there does not appear to be any plan to trade him, even though he was No. 3 on the depth chart when all three quarterbacks were healthy late in the season.
McCoy, who was originally signed to be the No. 3 quarterback last season, would have ended last season as the starter, but he was sidelined by a shoulder/neck injury.
The 27-year-old wound up starting four games for the Redskins last season, and he came off the bench to rally them to victory in a fifth.
He led the Redskins to a 20-17 win at Dallas on "Monday Night Football" in his first start. In that game, McCoy completed 25 of 30 passes for 299 yards and an interception.
McCoy started three more games before a neck injury ended his season after Week 14. For the season, McCoy completed 91 of 128 passes for 1,057 yards, four touchdowns and three interceptions.
A third-round pick out of Texas in 2010, McCoy spent his first three seasons with Cleveland before playing one year in San Francisco. He has made 25 starts and has a career passer rating of 78.2.
John Keim of ESPN.com contributed to this report.