Phil Parkinson is keen to add a left-sided defender to his ranks before the October 16 deadlines, and could also add a centre back following Morgan Feeney’s injury.
So who could be available in the free agent market? Scroll down and click through the pages as we take a look at the players Sunderland could consider:
1. Ben Heneghan
Released by Sheffield United this summer, Heneghan offers a wealth of experience in the third tier courtesy of a temporary stint at Blackpool. He's been linked with Sunderland in the past, but may well expect first-team football - something with the Black Cats may be unable to guarantee. Photo: Shaun Botterill
2. Lloyd Jones
A graduate of Liverpool's famed academy, Jones was released by Luton Town in the summer and is still looking for a new club. He's experienced and versatile across the back line, which could prove an attractive trait. Photo: Nick Taylor/Liverpool FC
3. Matthew Connolly
Connolly has been on the books of both QPR and Cardiff City in the Premier League and has vast experience in the Championship - something which could prove attractive to a number of clubs. But his salary and playing time expectations may mean he is not a feasible option for the Black Cats. Photo: Stu Forster
4. Jozo Simunovic
The Croatian youth international was allowed to leave Celtic this summer and is still on the lookout for a new club. His wage demands may render him out of the read of League One clubs under the new salary cap regulations, but he'd be an impressive capture for any club that could find a way to do a deal. Photo: Mark Runnacles