Williams has a history of being overweight and dealing with injury problems. He's listed at 6-foot-5, 235 pounds.
The former USC star caught only 18 passes for 236 yards and one touchdown last season.
His contract included base salaries of $3 million and $3.4 million in 2012 and 2013 in addition to $150,000 annual weight clauses.
Mike Williams was also due a $15,625 roster bonus for every game he was active for a total of $187,500, plus a $150,000 workout bonus.
“We would like to thank Mike for his contributions over the past two seasons and we wish him well in the future,” Seahawks general manager John Schneider said.
A former first-round draft pick of the Detroit Lions selected 10th overall, Williams signed with the Seahawks two years ago and caught a career-high 65 passes for 751 yards and two touchdowns to revitalize his career.
Williams has previous stints with the Oakland Raiders and the Tennessee Titans.
For the Seahawks, he caught 83 passes for 987 yards and five touchdowns.
For his career, Williams has caught 127 passes for 1,526 yards and five touchdowns.
The Seahawks' best wide receivers left on the roster are Sidney Rice, Golden Tate and Doug Baldwin.
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