Posted by ESPN.com's Tim Graham
We've seen this development coming for months.
That would mean Harrison's playing days are done, and in five years he'll be considered for the Pro Football Hall of Fame.
Harrison suffered a season-ending torn right quadriceps in Week 7. It was his fourth significant injury in four seasons. His contract was up. He's 36 years old.
And when Harrison moonlighted as a broadcaster, he elicited rave reviews. He's comfortable on camera and offers strong opinions.
He established a June 1 deadline to decide what he would do. He declared he would play only for the Patriots, but it was time to part ways. Brandon Meriweather played well in his stead. Then they drafted Patrick Chung and signed free-agent Brandon McGowan, clear indicators they're moving on at Harrison's old position.
What will Harrison's legacy be?
He has borderline Hall of Fame credentials that are worth debating.
He's the lone player in NFL history with at least 30 sacks and 30 interceptions. He was defensive captain for two Super Bowl champions. He went to a pair of Pro Bowls, both as a San Diego Charger. He was named first-team All-Pro once for each team. He was a vocal leader and a ferocious hitter.
Perhaps Harrison's biggest hurdle to overcome for induction into Canton will be the fact just seven full-time safeties have gotten in: Jack Christiansen, Ken Houston, Paul Krause, Yale Lary, Emlen Tunnell, Larry Wilson and Willie Wood. None of them played after 1980, and only two played beyond 1972.
What do you think? Does Harrison belong in the Pro Football Hall of Fame?