Head coach Alex Neil has previously said he still wants around four additions, and those deals could lead to some outgoing movement as well.
Neil expects some deals to go right to the wire, but is confident of one or two breakthroughs before next Wednesday.
We run you through the deals that could still happen here...
1. GOALKEEPER MOVEMENT
Alex Neil spoke earlier this summer of the need to replace Lee Burge and Thorben Hoffmann, and with only Alex Bass arriving it raises the possibility of another addition before the end of the window. What you would also say is that Anthony Patterson's excellence means that this no longer looks like anything near the priority it was a month or so ago before Bass was signed from Portsmouth. Patterson has looked every inch a Championship goalkeeper and looks very unlikely to be shifted any time soon. A serious, serious prospect for Sunderland. What a new arrival might do is allow Jacob Carney to go on loan, which is something he probably needs at this stage of his career. Priority Rating: Medium to low Photo: FRANK REID
2. JAN PAUL VAN HECKE
Neil was stressing the need for cover in defensive positions even before Dan Ballard suffered a broken foot that sees him sidelined for the foreseeable future. That they can clearly offer van Hecke considerable playing time is attractive to both Brighton and the player. With a year left on his contract, that is an issue that needs resolving before any loan would be sanctioned. But it's understood that if (or more likely when) that is sorted, Sunderland lead the race. Given he was named Blackburn's player of the year last season, it would be a considerable coup if Sunderland could pull it off. Over time, he can also compete for the central role in the back three. Priority rating: Very high, and signs currently very good Photo: Warren Little
3. CORRY EVANS
Neil has spoken about a lack of cover in some 'specialist' roles and it's hard not to leap straight to Corry Evans here. He excels in the holding role, and the poise he brought Neil has plenty of midfield options, but no one else at such ease with what is an important defensive and transition role. You could also argue that it's a similar story on the left of defence, where Dennis Cirkin is the only specialist left back. In the current 3-5-2 system, though, it doesn't look like quite so great a priority. Time will tell. Priority rating: High, surely Photo: Frank Reid
4. EDOUARD MICHUT
Respected transfer reporter Fabrizio Romano reported on Tuesday that Sunderland had opened talks with PSG for the 19-year-old. A forward-thinking central midfielder, it's a slight surprise given that Dan Neil, Elliot Embleton and Alex Pritchard have all impressed at different stages of the nascent season. Michut, though, is already a Ligue 1 winner and comes with a formidable reputation. It would be an eye-catching move if it came off. Competition is believed to be significant. Priority rating: Not a key position, but perhaps just too good an opportunity for Sunderland not to explore. Photo: Charlotte Tattersall