Reed explained his decision to ESPN's John Keim:
"I was pretty sure I was going to keep playing; I was feeling good about where I was at. But then I had some lingering effects and sought out professional help to get diagnosed. They told me it was not a good idea to keep playing. I agreed with them.
"Before when I had a concussion I would feel better afterwards and I wouldn't have lingering effects. If I didn't have any symptoms I would have kept playing. I'm OK with it because I know the reason why I'm making the choice is for family and my children, so I can be there for them. It's just time."
Ian Rapoport of NFL Network reported Tuesday that Reed, who spent the 2020 season with the San Francisco 49ers, felt his comeback with the Niners after missing the 2019 campaign allows him to "walk away with no regrets."
Reed developed into one of the league's most productive tight ends after Washington selected him in the third round of the 2013 draft out of the University of Florida.
His best statistical season came in 2015 when he recorded 87 receptions for 952 yards and 11 touchdowns. He earned his only Pro Bowl selection the following year with 66 catches for 686 yards and six scores.
Injuries were a constant factor in his career, though. He never played more than 14 games in any season and missed 49 of 128 regular-season contests during his eight NFL seasons. That includes sitting out all of 2019 after suffering his seventh documented concussion.
In September, Reed told reporters he almost retired last offseason before getting the urge to attempt a comeback with the Niners:
"I definitely thought about hanging it up after last season. But it was when I saw the Super Bowl that really kind of ignited me again. I want to play in those big games. God blessed me to be here and a part of this great team and gave me the opportunity to be in that situation. That's what's driving me. I love the game of football."
The 30-year-old Connecticut native tallied 26 catches for 231 yards and four touchdowns in 10 games during his final NFL season. He also spent time on injured reserve with a knee injury.
Reed finishes his career with 29 trips to the end zone in 76 career appearances, including one in his only playoff game during the 2015 season.