But he returned to reserve team action in 2010 and came on as a late substitute in United's 1-0 win over Sunderland in the penultimate game of the season on 2 May.
The Canadian-born Englishman came on for three minutes at the end of that match but did not feature in the final game, a 4-0 win over Stoke on 9 May.
Ferguson also fears centre-back Rio Ferdinand will not be ready for the first game of the season against Newcastle on Monday 16 August.
Ferdinand suffered a knee injury in training ahead of England's World Cup group stage match with the United States in June and was unable to play any part for the national side in South Africa.
Ferguson said: "Rio will probably not make the start of the season. It will be close. It depends on his progress over the next few weeks."
But while Hargreaves and Ferdinand look likely to miss the start of the season, United trio Antonio Valencia (hamstring), Nani (shoulder) and Michael Owen (hamstring) should be fit.
And midfielder Anderson is also making good progress in recovering from the cruciate knee injury he suffered in late September.
"Antonio Valencia should be okay and Nani should be ready for the start of the season, too," confirmed Ferguson.
"Michael Owen is doing great - he's doing all his work in the gymnasium every day. I don't think he'll be fit to go to America but he should be ready for the start of the season."
United leave for their training camp in Chicago on Monday 12 July.
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