The news comes after January centre-back signing Bailey Wright was ruled out 8-12 weeks with an ankle ligament injury sustained as the Black Cats defeated Oxford United 1-0 at the Kassam Stadium last Saturday.
But who could the Sunderland potentially sign? Here, we round-up the free agent options available now the transfer window has shut.
Simply scroll down and click through the pages.
1. ADAM CURRY
The 22-year-old Jarrow-born defender has been without a club since being released by Hull City last year. However, the ex-Boston United loanee lacks experience, with just 18 professional games under his belt. Photo: YASUYOSHI CHIBA
2. JOE MUSCATT
The 22-year-old defender was released by Tottenham after a loan with Salford City. Again, the youngster lacks experience with just five professional games under his belt. Photo: Tony Marshall
3. JAKE WRIGHT
Wright, an experienced centre back, was released by Sheffield United on Deadline Day. Oxford fans were calling for Karl Robinson to bring him back to the Kassam Stadium. He could yet prove an ideal short-tern option for Parkinson. Photo: Nathan Stirk
4. ALAN SHEEHAN
Released by Luton Town on deadline day, Sheehan has a wealth of League One experience and helped the Hatters to promotion last season. His set-piece delivery can prove a vital weapon. Photo: Pete Norton