The window is set to reopen on June 10, while Sunderland are already exploring the possibility of re-signing some of their former loan players from the 2021/22 campaign.
We asked Sunderland fans on our Facebook and Twitter accounts to name a realistic signing they would like the club to make this summer.
Several of you got in touch to share your views.
Here are some of the names that were mentioned:
1. Nathan Broadhead (Everton)
Sunderland have opened talks with Everton about the possibility of re-signing Broadhead, who impressed while on loan at the Stadium of Light last season. The 24-year-old has a year left on his contract at Goodison Park. Photo: National World
2. Jack Clarke (Tottenham)
Another player Sunderland could look to bring back to Wearside. The 21-year-old also has just a year left on his contract at Tottenham after making 20 appearances for the Black Cats during a loan spell in the second half of last season. Photo: National World
3. Dion Sanderson (Wolves)
Since his season at Sunderland during the 2020/21 campaign, the 22-year-old defender has spent time on loan at Birmingham and QPR in the Championship. The Black Cats are said to be interested in re-signing Sanderson, who signed a long-term deal at Wolves last summer. Photo: Cameron Smith
4. Tom Lawrence (Derby)
The Welshman’s contract at Derby is set to expire this summer following The Rams’ relegation to League One. Several clubs have already been credited with interest in the 28-year-old. Photo: Bryn Lennon