Jake Clarke-Salter is expected to be fit to face Bristol City on Saturday afternoon, meaning Chris Coleman is set to continue with a five-man defence.
Billy Jones struggled against Ipswich Town after stepping in as an emergency third centre-back, with Sunderland eventually switching to a flat back four.
However Clarke-Salter, who had been struggling with a hamstring problem, is fit again and Coleman says it will be the mentality of his team, rather than the formation, that defines the game.
He said: "Jake is going to be OK, so we have the bodies back to continue with the same system.
"At the end, just to ask Ipswich a different question, we switched formation.
"But whether we go to a four or a three, we are concentrating more on mentality and personality rather than any particular tactic.
"I've won games using all sorts of different formations – and lost them, too – but when I've won games it's generally because of mentalities and personalities."
Coleman also confirmed that Callum McManaman has been struggling with an injury to his shin.
The winger has not been part of the last two matchday squads but is now closing in on a return.
Coleman added that Paddy McNair and Jonny Williams will travel with the U23 side to face Exeter City on Sunday, meaning they will be not be involved at Ashton Gate.
He said: He got a kick on the outside of his shin in training.
"He ran indoors and got a bit of soreness after that and wasn't able to train because of it.
"It's not like him – since I have been here he hasn't missed a day's training, he's always been available.
"But in the last few weeks he has struggled, he's had bruising on it. He should be OK next week.
"Marc Wilson is a no [for Bristol City], he should be OK by next week," he added.
"Paddy McNair will get some gametime with the U23’s on Sunday, as will Jonny Williams and Brendan Galloway.
"[Adam] Matthews will be another three weeks we think, we’re not sure on a timescale for Lamine."