"I don't think any of them will be fit for Saturday [against Fulham]," The Express quotes Ferguson as saying. "Hopefully Jonny Evans is getting near.
"Obviously we've got a good week's training now and that will bring him on a good bit. Hopefully in a couple of weeks we should be okay. Defence has been a problem for us this pre-season.
"We lost Jones when he came back injured from the England set-up, Smalling broke a metatarsal in training, Evans had an operation in the summer, then Rio called off. That's four centre-backs. It's a concern, but we have to get on with it. There is nothing we can do about it."
The former Premier League champions sit 16th in the league table following the opening weekend of the new campaign.