Per ESPN's Adam Schefter, Marshall was released by the Seahawks after appearing in six games for the team this season.
Schefter added Marshall "absolutely" wants to continue his playing career.
After injuries limited Marshall to five games with the New York Giants in 2017, he signed a one-year deal with the Seahawks in May. The 34-year-old came into this season with the goal of playing well enough to be named NFL Comeback Player of the Year.
"I'm a competitor," Marshall told Gregg Bell of the News Tribune in September. "That's why I'm here. And I think the reason why I'm still playing is because I never felt like I've ever arrived, right? I always feel like you can get better. Definitely had to overcome a lot of obstacles. But that (award) is the goal. That's my mindset."
Marshall started the year as a prominent part of the offense, receiving six targets in each of Seattle's first three games. He was only targeted five times in the next three games but didn't play in Week 8 against the Detroit Lions.
In six games with the Seahawks, Marshall finished with 136 yards and one touchdown on 11 receptions.