Reed suffered a concussion in the third preseason game after a helmet-to-helmet hit by Atlanta Falcons safety Keanu Neal, who was penalized and eventually fined. Reed has not played since, although he did return to practice.
League sources told ESPN's Adam Schefter last month that there is concern that Reed's career is over due to his history of concussions.
It is believed to be Reed's seventh concussion since he started playing college football. He has two years remaining on his contract, part of a five-year deal signed after the 2016 season. If the Redskins cut him after the season, they would save $8.5 million in cap space for 2020.
Reed, 29, was a limited participant in practice during the first two weeks of the season, participating in individual drills with his helmet on. The Redskins were optimistic he would play in Week 2 against Dallas and he was part of the game plan, but when Reed was unable to practice the Friday before that game, those hopes were dashed. He has not been on the practice field since.
When healthy, Reed was a key part of the Redskins' passing attack. His ability to win with quick, explosive route running made him dangerous to cover one-on-one, especially for a linebacker. Teams often paid close attention to him, providing an opening for others on the offense, but injuries often got in the way of his productivity.
In Reed's first six seasons, he never played more than 14 games. Two years ago, he played only six. Reed was bothered by issues with the ligaments in both of his big toes in recent years, but he was finally healthy this offseason, allowing him to train rather than rehab. He was a standout in training camp practices because he had regained some of the explosiveness lost over the past two seasons.
Reed, a third-round pick out of Florida in 2013, had a breakout third season. That year, while playing in 14 games, he caught 87 passes for 952 yards and 11 touchdowns as the Redskins won the NFC East. In his career, Reed has caught 329 passes with 24 touchdowns.
His absence has been felt by Washington's offense, especially with fellow tight end Vernon Davis already declared out for a second consecutive game with his own concussion. Jeremy Sprinkle, in his third season and primarily a blocker, is the team's No. 1 tight end entering Sunday's game against the Miami Dolphins (0-4).
The Redskins (0-5) promoted safety Jeremy Reaves off the practice squad to take Reed's roster spot.