But which former Black Cats stars are now free agents having been released by clubs and which players will see their deals expire soon?
Here, we take you through all of the ex-Sunderland players who have been released or are soon to be released.
Are there any realistic targets that the Black Cats could look to re-sign?
Scroll down to take a look at the list:
5. Keiren Westwood
Keiren Westwood spent three seasons at Sunderland between 2011 and 2014 before moving to Sheffield Wednesday. However, following the club's relegation to League One, the goalkeeper has been let go. Photo: Alex Pantling
6. Jerome Sinclair
Jerome Sinclair, who spent half a season on loan at Sunderland during the 2018/19 campaign, is now a free agent after leaving Watford. Photo: Dan Istitene
7. Declan John
Declan John failed to make a single appearance on Wearside after joining on loan during the 2019/20 season. The Wales international full-back is now a free agent after leaving Swansea City. Photo: Stu Forster
8. Phil Bardsley
The former Sunderland right-back, 35, is out of contract at Turf Moor this season with a decision yet to be made on his future. Photo: Alex Pantling