The Seahawks didn't extend a tender to Mutcherson, making him an unrestricted free agent, John Boyle of the team's official site reports.
Mutcherson spent all of last season on injured reserve after sustaining a knee sprain during the preseason. The 26-year-old should now be healthy, and will seek out a reserve role elsewhere in the league.
Mutcherson suffered a knee sprain in the second half of Thursday's preseason game against the Colts, The Seattle Times reports.
Coach Pete Carroll believed it was a minor sprain for Mutcherson, who did not record a tackle prior to the injury. The 26-year-old signed a deal with the Seahawks in May and is battling for a roster spot as a reserve safety.