But which players are still available this summer who could be interesting the Black Cats? We take a look at the best players still available who could realistically arrive at the Stadium of Light in the coming weeks – scroll down and click through the pages to see who could be available as transfer business ramps up:
1. Chris Cadden (Free Agent)
Cadden has been heavily linked with Sunderland this summer, but there is interest in the wideman from the MLS and fellow English sides after he snubbed a new deal at Motherwell.
Photo: Mark Runnacles
2. George Boyd (Free Agent)
Having left Sheffield Wednesday this summer, the experienced winger is available for free this summer and - although he may be looking to remain in the Championship - could prove an attractive proposition for Sunderland.
Photo: Catherine Ivill
3. Joel Lynch (Free Agent)
Defensive recruits are a priority for Jack Ross this summer and the experienced Lynch would be a handy acquisition in that department.
Photo: Warren Little
4. Will Keane (Free Agent)
The former Manchester United striker was released by Hull City this summer and will be looking to reignite a once-promising career. Could Sunderland be the place to do that?
Photo: John Peters