Manchester City will check defender Vincent Kompany after training on Friday before deciding whether he can feature at Southampton.
Kompany has been sidelined by a calf injury that was expected to keep him out until after next week's FA Cup fifth-round tie with Leeds. However, the Blues skipper returned to training on Wednesday and could be available at St Mary's.
"We are optimistic," said manager Roberto Mancini. "He trained yesterday, and two days ago. After today we will decide."
"I am sorry because they didn't win but I am happy because they are here," said the Italian.
However, he said City's hopes will be aided by United's continued progress in the Champions League, where they face Real Madrid on Wednesday.
"It is normal when you play against Real Madrid you can lose some strength," he said.
"I will be supporting United to go through."