But could any of them prove of interest to current manager Phil Parkinson, who is set to lead an overhaul of his squad this summer?
Scroll down and click through the pages to see the former Black Cats available as free agents this summer – and let us know whether there are any you would take back:
9. Will Buckley
Another player recently on the books of the Trotters, Buckley looks set to head to a new club in the summer as he looks to revive his career. Photo: Laurence Griffiths
10. Darron Gibson
Gibson has already been released by Salford City, and now faces an uncertain future as he bids to find a new club. Photo: Nathan Stirk
11. Jack Rodwell
Rodwell has signed a contract to keep him with Sheffield United until the end of the current Premier League season, but the Blades won't be extending his contract past that point. Photo: Michael Regan