The Black Cats broke the British record for the highest fee for a goalkeeper when then-manager Roy Keane paid Hearts £9 million for the Scotland international in 2007.
However, he made just 95 appearances in five years and joins fellow stoppers Trevor Carson and Lewis King, defenders Liam Bagnall and Jordan Lavender, midfielders James Brace and Brett Elliott as well as strikers Jordan Cook and Oumare Tounkara out of the exit door.
A succession of injuries and inconsistent form contributed to Gordon failing to fulfil his potential at the Stadium of Light. He broke his arm twice, and suffered niggling injuries on a constant basis, while a knee tendon and anterior cruciate ligament injury picked up in April last year meant he was ruled out for eight months.
Belgian Simon Mignolet has established himself as the first-choice goalkeeper in Gordon's absence with Keiren Westwood, signed last summer as a result of Gordon's injury woes, understudy.
Gordon made just one appearance all season - against Bolton last month - and boss Martin O'Neill has decided the Scot, who has represented his country on 40 occasions, no longer figures in his plans.