Phil Parkinson is keen to add a left-sided defender to his ranks and is still able to add unattached players to his side even though the transfer window has closed.
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:
5. Charlie Daniels
Daniels has spent time training with Bournemouth this summer - and has played in some friendlies - but is technically a free agent after his contract expired. Could a drop down to League One appeal? Photo: Michael Regan
6. Junior Brown
Released by Coventry in the summer, Brown spent time on loan with Scunthorpe last season but has previously played regularly in League One. Maybe not the most glamorous option, but could perhaps offer a good amount of cover - if not competition - for Denver Hume. Photo: Pete Norton
7. Ali Koiki
Reports suggested the former Burnley man was on Sunderland's radar earlier this summer, while Charlton and Bristol Rovers have also been credited with an interest. He was expected to sign for the Gas before the transfer window closed but that deal has stalled - which could open the door to another side to swoop in. Burnley will be due compensation when a deal is done, though. Photo: Alex Davidson
8. Sean Kelly
Released by Ross County in the summer, Kelly has previously played in League One with AFC Wimbledon. He's another name that may not get people too excited, but he could be a good backup option for Hume - who is the Black Cats' undisputed first choice on the left flank. Photo: Harry Murphy