Speculation surfaced in the aftermath of United's defeat at Manchester City on Monday that the Scotland skipper had lost his battle against a chronic bowel condition, which forced him to take a break from the game in December.
Club sources quickly rejected that notion, which Ferguson has now backed up. It is still hoped Fletcher will play some part in United's pre-season programme.
However, as Ferguson acknowledged, an accurate assessment of Fletcher's condition is not easy because the Scotland captain is still being treated by his own medical people.
"We're hoping he will start pre-season training," Ferguson said. "He is on the recovery road at the moment in the sense of some work he is doing, but we can't assess it because we don't know enough about it.
"Darren's medical people are dealing with it and our doctor has a good idea of the situation but at the moment the boy is doing his best to come back."