Vidic has been out of action since suffering knee ligament damage in December.

"Chris Smalling is out for 10 weeks with his metatarsal operation and Jonny Evans is still just in light training,"Ferguson told reporters.

"They’re big losses at the moment and they will miss the start of the season.

"Rafael is away [with Brazil at the Olympics] and Fabio is away on loan so there are four defensive players that we don't have for the back four positions.

"We do have Phil Jones, Nemanja Vidic, Rio Ferdinand and Patrice Evra, though. That will be the back four on tour. Hopefully we don’t get any more injuries as it would leave me a bit short."