Vidic has been missing since rupturing cruciate ligaments in December, whilst Smalling required a groin operation that ruled him out of contention for Roy Hodgson's Euro 2012 squad.
However, Jonny Evans is unlikely to face Everton at Goodison Park on August 20 after a summer ankle operation.
"Jonny has had an operation," said Ferguson. "I am not sure he will start the season but he won't be far away.
"Chris Smalling has done a bit of training. The ruptured groin muscle he had certainly needed a lot of attention. He is gradually progressing and I expect him to start the season."
That could be good news for Hodgson ahead of England's friendly with Italy in Berne on August 15.
However, United fans will be buoyed by the positive news on Vidic, whose absence in the vital games at the end of last season was viewed as a major factor in the points dropped to Wigan, Manchester City and, catastrophically, Everton which ultimately cost the Red Devils their title.
"Vidic will start the season, I am sure of that," said Ferguson.
"He is still at the level of doing good amounts of training but not in the competitive sense that the others have done so it was pointless bringing him out here.
"He is better being back at Carrington, with all the facilities and the physios to get him to the next level. By the time we get back, we hope he is at the competitive element of his comeback."