The team announced in the second half he was considered doubtful to return to the game.
He had one catch for five yards against the Dallas Cowboys at FedEx Field on Sunday before suffering the injury attempting to run a route.
Injuries have limited Reed throughout his career, as he's failed to complete a 16-game season in any of his first four years in the league. He missed four games last year while dealing with a concussion as well as a shoulder injury.
It appears yet another problem will limit the player while forcing the Redskins to look further down the depth chart for solutions.
When healthy, Reed is a dominant tight end who ranks among the best in the league at his position. He earned a Pro Bowl spot last season while tallying 686 receiving yards and six touchdowns in 12 games. In 2015, he needed only 14 games to grab 11 touchdowns with 952 yards.
This season hasn't featured as much consistency, but he still entered Week 8 with 206 yards and two touchdowns, both coming last game against the Philadelphia Eagles.
With the latest injury, the Redskins will instead have to turn to Vernon Davis to make plays at tight end. Receivers Ryan Grant and Jamison Crowder should also get extra targets with Reed out.