The contract is a one-year deal worth a maximum of $2 million, per Adam Schefter of ESPN.
Marshall announced the signing Tuesday on Instagram, via football reporter Dov Kleiman:
Jordan Raanan and Schefter of ESPN first reported the receiver's visit to the Seahawks earlier this month, and it seems it went well.
While Doug Baldwin and Tyler Lockett should remain in key roles, the team needed another big-bodied player who can help in the red zone. Aside from the unproven Tanner McEvoy (6'6", 230 lbs), the pass-catchers on the roster are generally undersized.
The 6'5", 232-pound Marshall could be a quality target for Russell Wilson next season while bringing a different dynamic to the offense.
The New York Giants released Marshall, 34, in April with a failed physical designation after he missed all but five games last season with an ankle injury. He struggled even when he was on the field, totaling just 18 catches for 154 yards and zero touchdowns.
It was by far the worst season of his career, which includes six Pro Bowl selections, one first-team All-Pro nod and eight campaigns with at least 1,000 receiving yards.
With the retirement of Dallas Cowboys tight end Jason Witten, Marshall ranks second among active players with 959 career receptions and 12,215 receiving yards. His total of 82 touchdowns is sixth among all active players, including running backs, receivers and tight ends.
Although he is coming off a pair of disappointing campaigns with the New York Jets and Giants, he is just a couple of years removed from one of the best seasons of his career.
Marshall finished 2015 with 109 catches for 1,502 yards and an NFL-best 14 receiving touchdowns.
While he might not be able to replicate this type of success in Seattle, he can still make a significant impact on the field if he can stay healthy.