Ian Rapoport of the NFL Network confirmed Lynch was retiring and had informed the Seahawks.
The Seahawks thanked Lynch for his time in Seattle:
Lynch, who turns 30 in April, was limited to seven games in 2015 because of sports hernia surgery. He compiled just 417 yards and three touchdowns on the ground, by far his worst numbers in a Seahawks uniform.
His return to the starting lineup in the divisional round was anything but helpful, as Lynch's longest carry went for nine yards. The Seahawks were forced to throw the ball 48 times after digging themselves into a 31-0 hole against the Carolina Panthers in the first half.
"It wasn't his fault," quarterback Russell Wilson said after the game, per Rich Cimini of ESPN.com. "It was my fault. So just, 'Head in the game, let's stay in the moment, a lot of game left.' Marshawn did great, just in terms of being in it. Obviously, him coming back was a tough situation physically, but he stepped up to the challenge. I'm grateful for that."
The tone after the game was understandably somber, with teammates speaking of Lynch cryptically in the past tense.
Cornerback Richard Sherman openly discussed how he would "remember" Lynch if he were to leave, per Cimini:
He's a beast, he's a workhorse. He's a guy who's going to go out there, if he's strapping up his pads, and give you everything he's got. He'll play his heart out and play until the last whistle. That's what you can appreciate. He's an outstanding teammate and an outstanding guy, on and off the field. I'll remember him as a phenomenal person who will give you the shirt off his back.
Lynch was scheduled to make $9 million in base salary next season. His contract would of had a cap hit of $11.5 million.
The cap hit wouldn't have been much of a problem in years past, as Seattle was lucky enough to have most of its core bound by rookie contracts. With Wilson, Sherman, Bobby Wagner and Earl Thomas all locked into high-cost, long-term deals, Seattle now has to be far more frugal with its roster.
The emergence of Thomas Rawls in Lynch's absence should make it easier to move on. Rawls is recovering from an ankle fracture, but he was one of the best running backs in football when healthy. His cap hit is a meager $530,000 next season and $620,000 in 2017.