Wayne Rooney is set to miss the start of the season after picking up a virus on United’s pre-season tour of Africa.
The England striker will not be fit to line up for United in the Community Shield against Portsmouth on Sunday, and is also likely to sit out the Premier League opener against Newcastle the following week.
The news will come as a major blow to United, who will also begin the defence of their title without injured winger Cristiano Ronaldo.
Nani, who is suspended, and Anderson, on Olympic duty with Brazil, will also be unavailable for the opener against Newcastle.
“I’m starting to worry about whether we are going to have a team ready for the start of the season, because Nani is suspended, Anderson is at the Olympics and I doubt if we will get Rooney fit after the virus he has had,” Ferguson told Sky Sports News.
“He picked it up in Nigeria and it’s not a nice one. It’s 12 days to the season starts and he’s not been able to train.”