United have major defensive worries for the first leg of Tuesday's last 16 tie at Giuseppe Meazza as the holders continue their defence of the title.
Nemanja Vidic is suspended for the game, while Gary Neville, Wes Brown and Rafael all failed to travel with the squad for the match.
Evans and O'Shea are in the squad, but are doubtful due to ankle and heel injuries respectively, with a decision expected to be made at the last minute.
Northern Ireland international Evans limped out of Saturday's 2-1 win over Blackburn with a recurrence of his ankle problem and he did not train on Monday evening at the Giuseppe Meazza.
O'Shea did take some part in training and United boss Ferguson admits he will have to leave it late before finalising his team to face Inter.
Big concerns"The options are: panic. I think I can play Dimitar (Berbatov) as sweeper," joked Ferguson at his pre-match press conference.
"I hope one of them will make it. O'Shea might, then we have the problem at right-back.
"Obviously we have some injury problems and we won't know until tomorrow for O'Shea. He did a little light session on his own, not with the other players. Jonny Evans wasn't able to train.
"These are the major doubts, but everyone else is fit and travelled.
"Obviously these are the big concerns with Wes Brown and Gary Neville both injured and Nemanja Vidic suspended.
"It's a worrying moment for us, but in the context of our club we've accepted it and got on with it."
Ferguson also confirmed United will be trying to win the match following Inter coach Jose Mourinho's claim that the visitors would play for a draw.
Challenge"I'm sure Jose has seen us enough to know that we very seldom go into a game not trying to win and that won't change tomorrrow," added Ferguson.
"We have the challenge of having to play in a stadium tomorrow with such a fantastic crowd that will help the players, I'm sure of that.
"I wish we were in a better position tomorrow defensively in terms of availability, but that happens in football, we have to carry on with the competition tomorrow.
"We still have the opportunity to take Inter back to Old Trafford with a good result. If we score an away goal it will give us a great chance.
"You're always intent in Europe to get that goal that means something really big when you get back to your own ground."