Sir Alex Ferguson said he does not expect Nemanja Vidic to return to the Manchester United side for at least another week.
The Serbia international was being touted for a comeback in United's Champions League clash against Cluj on Wednesday evening after more than two months on the sidelines following knee surgery.
However, Ferguson says the 31-year-old is still short of full fitness and will not be considered for this weekend's derby clash against Manchester City either.
"I do not think he will play," said Ferguson. "He feels he needs another few days' training.
"He will not play in the derby if he doesn't play on Wednesday, although I wasn't considering him for Sunday anyway."
Ferguson also confirmed that Japan midfielder Shinji Kagawa has an outside chance of being involved in the derby after returning from a knee injury of his own.
"He's showing good promise now. It is much better and I don't think he is far away," said Ferguson.