Edwards, 29, was drafted by the Cleveland Browns in 2005 out of the University of Michigan. He was named to the Pro Bowl in 2007, after catching 80 passes for 1,289 yards and 16 touchdowns.
He spent last season in San Francisco where he struggled, but the previous two seasons with the New York Jets where he was more effective.
Edwards was expected to practice with the Seahawks on Tuesday. Kicker Carson Wiggs was waived to make room for him on the roster.