England international Hargreaves has undergone surgery on both knees in the past 12 months and has spent much of his time in the United States undergoing rehabilitation.
"Owen's doing a lot of good work now and we're pleased with that," Ferguson told reporters at his news conference before Saturday's Premier League match against Bolton Wanderers.
"As I said when he came back to Manchester, it's not something we need to rush. Because he's been out for a year, we monitor it a bit more closely.
"But he's giving us good signs and he should be back at the first-team level three weeks from now, easily."
Former Bayern Munich player Hargreaves, who has 42 England caps, is running out of time if he is to stand any chance of appearing at next year's World Cup finals.
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Owen ruled out for up to three weeks