Winslow was acquired in May from the Tampa Bay Buccaneers. He caught 218 passes for 2,377 yards and 12 touchdowns in three seasons with the Buccaneers.
The veteran tight end caught three passes for 34 yards and a touchdown in the 2012 preseason, but had to have his practice time monitered because of chronic knee problems. He never played a regular season game with the team.
It is believed Winslow was released Saturday because he declined to take a cut in pay. Winslow was slated to make $3.3 million per season with the Hawks.
According to the Seattle Times, the Seahawks have agreed to terms with tight end Evan Moore. Moore caught 34 passes with the Cleveland Browns last season. Moore will join tight ends Zach Miller and Anthony McCoy on the Seahawks' roster.