He was expected to be ready for the new Premier League campaign but injured his toe in training on Wednesday and the surgery on the broken metatarsal means he will miss the start of the season.
"He got an injury on the Wednesday and, straight away, we decided to have the operation so he's out," Ferguson told the club's television channel MUTV. "It's difficult to say with a metatarsal but it could be 10 weeks.
"He's not carrying any luck, the kid, but he's young and we've done the right thing in getting it done immediately and getting him back on the road as quickly as we can."
United captain Vidic should be fit to start the season after a cruciate knee ligament operation but Evans is a doubt for the league opener at Everton on August 20 with an ankle problem.