"Hopefully we'll got a good proportion of the players back fit from their international exertions," he told manutd.com.
"We've got a lot of players all over the place. For example, Vidic and Berbatov are playing (against each other) in Belgrade and Michael Carrick is in Germany with England.
"Cristiano Ronaldo, Nani and Anderson are travelling across to Brasilia and I don't know when they get back. That's not an easy trip that."
"We'll need a strong side for Villa," he said, before reeling off the extent of United's current sick list.
"Rio did his back in during training on Friday, Wayne had a chest infection but also a calf strain and Gary Neville injured his groin against QPR and will be out for maybe a couple of weeks.
"Ryan Giggs couldn't play against Stoke after tweaking a hamstring. We had to take Darren Fletcher off because his knee is still very tender after his recent injury so we had to take him off. So a good week didn't come without a cost."