Manchester United have just three recognised defenders - Wes Brown, Gabriel Heinze and John O’Shea – for Tuesday’s Champions League semi final first leg against AC Milan at Old Trafford.

While Brown and Heinze, who plays in central role for Argentina, are likely to be at the heart of the United defence, O’Shea is expected to marshal the left-back position. That leaves the right-back spot open to a makeshift arrangement most likely to be filled in by Scotland midfielder Darren Fletcher.

Fletcher had done well in that position coming in the first half following Rio Ferdinand’s groin problem in the FA Cup semi-final against Watford last Saturday.

Defenders - Ferdinand (groin), Gary Neville (ankle), Nemanja Vidic (collar bone) and Mikael Silvestre (shoulder) are all out, so is striker Louis Saha (hamstring).

Meanwhile, specialist left-back Patrice Evra trained away from the group on Monday as he is recovering from a calf injury sustained against Sheffield United under a challenge from Collin Kazim-Richards.

The Frenchman is likely to be on the bench for the AC Milan match.

United boss Sir Alex Ferguson said: "The important players are available for (Tuesday), so the one problem I have is maybe I've an inadequate bench. .

"We're happy with the squad I'm playing. Obviously you do miss players likes Rio Ferdinand, Gary Neville in big matches and Louis Saha as well.

"The spirit of the team is good and Saturday's match (against Middlesbrough) was a game in which the injuries came for a bad time for us just on half-time.

"I think it's difficult to think we can get to the standard of result we got against Roma. These are once in a lifetime results, but I think we should still expect a very good performance.

"It's not going to be easy, but to get to the semi-final of this particular competition we're not going to get it easy. It's always going to be a difficult match.

"I don't have any fears about it. I've seen the mood in the camp and it pleases me. We've had concerns about one or two injuries, but important players are playing (Tuesday)."