The veteran receiver was released on Tuesday, the team announced.
ESPN's Adam Schefter first reported the news, noting that Marshall "absolutely" wants to keep playing.
Whether he can find a team to reciprocate that desire is a completely different question.
The 34-year-old receiver made the season-opening roster and started two games early this season. Ineffectiveness and the emergence of younger (and currently better) players pushed Marshall to the sideline and now to the NFL's breadline. He finishes his time in Seattle with 11 catches for 136 yards and one score.
The biggest reason for cutting Marshall is the emergence of second-year receiver David Moore. The 6-foot seventh-round pick has been a marvel this season, snagging catches that would make body contortionists blush, and providing a perfect pairing in Seattle's three-receiver sets.
As Moore's playing time increased, the need for Marshall decreased. The veteran played just two offensive snaps in Week 8 and 32 over the Seahawks' last three games combined.
When signing Marshall, the Seahawks hoped one of their young wideouts would step up to fill the void and overtake the veteran, making him superfluous. Moore is that man.