David Wagner confirmed that Ben Gibson has suffered a metatarsal stress fracture, ruling him out of the next few weeks of action.
Speaking ahead of the visit of Blackburn Rovers, the head coach spoke about the options available in the squad.
"Everyone is available apart from Ben Gibson, who will be out until Christmas. Everyone else looks fine and healthy from Sunderland.
"The good news is that he doesn't need surgery, but he will be out for a number of weeks and out until around Christmas.
"Grant Hanley will play tonight for the Under-21s, and we will look at him next week. We will not rush him, and we need to be sensible with him. We're looking forward to give him his first minutes tonight."
Wagner also spoke about youngsters Jaden Warner and Kellen Fisher, and how they can provide competition for the senior players in the squad.
"Jaden Warner is a squad member, and played fantastically in the cup. He's in contention for sure.
"I think we have a proper talent at our club here with Kellen Fisher. After Sunderland, everyone now knows this. It was his first league start against one of the best wingers in the league, and that makes his performance even bigger."
On the other returning players, Wagner said: "I'm super confident that Ashley Barnes will be back after the international break. He's on track and will be back after the break, with (Angus) Gunny as well.
"We can’t plan with Jacob Sørensen or put a time frame on when he can be back in training. He will see another consultant about another surgery next week."