Dallas missed Saturday’s Championship win at Bristol City after a family bereavement with head coach Thomas Christiansen revealing the winger had lost his mother.
Christiansen has already urged the 26-year-old not to rush back and the head coach confirmed that the Northern Ireland international would miss Tuesday night’s fourth-round clash at the King Power Stadium.
“He will be missing, yes,” said Christiansen.
United will also be without the suspended full-back Gaetano Berardi who will now serve a three-match ban for being sent off for headbutting Matty Taylor during Saturday’s win at Ashton Gate.
Christiansen confirmed that Manchester United loanee left-back Cameron Borthwick-Jackson will be in the squad with the 20-year-old looking at a possible shot at the first team in Berardi’s absence.
“He is in the squad so we will see tomorrow,” said Christiansen, who can also call on Vurnon Anita at left back.
Striker Ekuban, meanwhile, remains sidelined as he continues on the comeback trail after undergoing surgery to correct a broken bone in his foot.
Christiansen, though, says the 22-year-old is nearing a return.
United’s head coach revealed: “He is still injured but he has been working very well and very intensely during the last two weeks.
“In not a long time he will be available with the team.”