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:
5. Ross Wallace (Free Agent)
Another player with Sunderland links, versatile midfielder Wallace is yet to commit to Fleetwood Town and showcased last season how effective he can be in the third tier. Photo: Harry Murphy
6. Josh Bowler (Everton - loan)
Sunderland are crying out for some more creativity out wide, and exciting youngster Bowler would certainly fit the bill. Everton are willing to allow him to secure a loan move this summer. Photo: Harriet Lander
7. John Marquis (Doncaster Rovers)
A £1million fee is thought to be enough to prise the prolific striker from Doncaster Rovers - with Sunderland known to be fond admirers. With a striker addition looking necessary, Marquis could be a perfect fit. Photo: Ross Kinnaird
8. Herbie Kane (Liverpool - loan)
The Liverpool youngster excelled on loan at Doncaster Rovers last season and could be allowed to leave Anfield again. Interest will be high after Kane's stellar performances last season. Photo: John Powell