Wayne Rooney is set to miss the start of the season after picking up a virus in Nigeria.
Manchester United toured Africa last month and won the Vodacom Challenge before taking on Portsmouth in a friendly.
It has now emerged that Rooney is suffering from a virus and will not be fit to line up for United in the Community Shield against Portsmouth on Sunday.
The England man 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.
Ronaldo underwent ankle surgery earlier this summer and is not expected to return to action until October.
Nani and Anderson will also be unavailable for the clash with the Magpies and Sir Alex Ferguson is concerned about his lack of options.
"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."
Manchester United toured Africa last month and won the Vodacom Challenge before taking on Portsmouth in a friendly.
It has now emerged that Rooney is suffering from a virus and will not be fit to line up for United in the Community Shield against Portsmouth on Sunday.
The England man 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.
Ronaldo underwent ankle surgery earlier this summer and is not expected to return to action until October.
Nani and Anderson will also be unavailable for the clash with the Magpies and Sir Alex Ferguson is concerned about his lack of options.
"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."