And with a range of options being considered, the Black Cats may be eyeing the division above for potential recruits.
So which defenders are currently out of favour at their Championship clubs, and could they prove to be realistic targets for Sunderland?
We take a look at some potential options – simply scroll down and click through the pages to see who could be available:
We take a look at some potential options – simply scroll down and click through the pages to see who could be available:
3 / 3