The Serbian centre-half returned to training after six months as he suffered damaged knee ligaments in a Champions League match against FC Basel in December.
Vidic was joined by new signing Shinji Kagawa in training along with other players who did not participate in England's Euro 2012 campaign.
The return of their captain will boost Sir Alex Ferguson's troops as they try to reclaim the Premier League title from noisy neighbours Manchester City.
Japan star Kagawa, who made a switch from Borussia Dortmund for £17m, trained with United players for the first time after being officially unveiled on Thursday.
Ferguson also hinted at signing two more players with Brazlian teenage star Lucas Moura deal taking a new low as Sao Paulo chiefs are not willing to sell the playmaker even though it could be a big risk.
"It is a risk not selling Lucas, but we are going to take it," Sao Paulo president Juvenal Juvencio was quoted as saying in Daily Mail.
The Brazilan giants had earlier rejected a £32million bid from Chelsea and £15 million bid from Inter Milan. However, United were frontrunners to sign the 19-year old midfielder.
Jim Lawlor, Manchester United's chief scout had flown in to Brazil to seal a deal worth £25m but the Brazilian wizkid will to continue with Sao Paulo.