The centre-back was out of the side in the main for last season after suffering with ruptured knee ligaments in the Champions League defeat to FC Basel.
On top of that Phil Jones and Jonny Evans are also struggling to get fit in time for the big kick-off, both are still suffering with foot injuries.
Then of course there is Chris Smalling whose damaged metatarsal will keep him out of action until October at the earliest.
Sir Alex Ferguson told Goal.com: “It’s not 100% Evans and Vidic will start the season. Jonny will start running today. Vida [Vidic] and Phil Jones started full training today.”