United entertain Everton today at Old Trafford.
Ferguson said: "David (Moyes) has had terrible injuries, with (Phil) Jagielka and (Mikel) Arteta being out for a long time now. Phil Neville's been out, as have (Leon) Osman and (Steven) Pienaar, so he's facing much the same situation as ourselves at the moment.
You can understand how difficult it is to win games when you've not got your strongest team available. Everton are very powerful opponents; a very determined side. You need to perform to win games, and we'll need to perform tomorrow. Once David gets his full squad back, he'll come up the table again."