Evans missed the 1-0 defeat at the Etihad Stadium in a game which saw Welbeck suffer an ankle injury which led to him wearing a protective cast after the game.
Ferguson will have to do without both Evans and Welbeck for the game at Old Trafford as his side look to take the title initiative back after Vincent Kompany's goal gave City the advantage, albeit on goal difference.
Ferguson said on Evans: "He has improved a little bit but (will) not (be fit) for Sunday." On Welbeck he added: "He is out. He got injured on Monday. Hopefully he will be ready for the Sunderland game."
Ferguson insisted his players had to deal with the setback against City and do their best to take maximum points from the final two games.
"We have to get over the disappointment of Monday. It was a blow to us. It has put us on the back foot. We can only do what we can do."