Per ESPN's Jordan Raanan and Adam Schefter, Marshall is visiting the Seahawks on Wednesday.
Marshall was released by the New York Giants on April 19 with the failed physical designation. The six-time Pro Bowler appeared in five games last season before being placed on injured reserve on Oct. 10 with an ankle injury that required surgery.
Prior to suffering his season-ending injury, Marshall had just 154 receiving yards on 18 receptions. He was averaging a career-low 8.6 yards per catch with no touchdowns.
The Seahawks have a need for more pass-catching playmakers after losing Paul Richardson and Jimmy Graham in free agency. That duo combined for 16 touchdown receptions in 2017.
After missing the playoffs last season for the first time since 2011, Seattle has made significant changes to its roster. Cornerbacks Richard Sherman and Jeremy Lane were released, and defensive end Michael Bennett was traded to the Philadelphia Eagles.