Lee Johnson has already brought in former-Spurs defender Dennis Cirkin and it looks likely that Leeds United’s Niall Huggins may join him.
With it looking increasingly unlikely that Denver Hume will remain with the club, while the Black Cats are also yet to sign a right-back, Sunderland are still on the hunt for more defensive additions.
The League One outfit have already snapped up two free agents in Alex Pritchard and Corry Evans and could potentially go down that route once again in their search for some full-backs.
We have found eight free agent full-backs that Sunderland could target in the final weeks of the window below...
1. Joe Bennett
Joe Bennett began his career with Middlesbrough and most recently played for Cardiff City. Bennett would be a very good signing for Sunderland but the 31-year-old is likely to attract interest from the Championship. Photo: Naomi Baker
2. Neil Taylor
Neil Taylor was released by Aston Villa at the end of last season and struggled for appearances following their promotion to the Premier League. Taylor may not want to drop down to League One but there hasn't been much talk of the 32-year-old being snapped up elsewhere this summer. Photo: Pool
3. Andre Wisdom
Andre Wisdom is an experienced right-back, enjoying spells with Championship teams such as Derby County, West Brom and Norwich. The Leeds-born defender was most recently released by Derby and, at only 28, will be on the search for a new club for the 2021/22 season. Photo: Shaun Botterill
4. Gaetano Berardi
Gaetano Berardi was recently released by Leeds United and, at 32, has bags of experience. The 32-year-old spent seven years with Leeds United in the Championship and also made a couple of Premier League experiences last season. Berardi played both right-back and centre-back during his time at Elland Road. Photo: Stu Forster