Phil Jones will play no part against Real Madrid, Sir Alex Ferguson confirmed today.
The defender missed Manchester United's open training session this morning, increasing fears the midfield enforcer would miss tomorrow's Champions League encounter.
Speaking to the media today, Fergson said: "He's not fit. He won't be fit for tomorrow."
Jones injured his ankle in the FA Cup victory over Reading two weeks ago, and was always doubtful for second leg last-16 tie.
However, the news is a major blow to United. In the first leg at the Bernabeu which ended 1-1, the former Blackburn Rovers player was pivotal in keeping Cristiano Ronaldo relatively quiet.
"His performance over there was excellent but we do have options and hopefully it is something we get right," said Ferguson.
Ferguson, who was in attendance at the Nou Camp when Real Madrid put on a stunning display of counter attacking football to beat Barcelona 3-1 last week, recognises the size of the task United face tomorrow.
"I think that both teams are in form," he said. "Real put in two fantastic performances against Barcelona. I was there on Tuesday and they were superb. They've found form at the right time for a game of this nature but we've been consistent for quite a while.
"As a European night I don't think you get better than this one, they're clubs with two great histories and it's set up to be a marvellous game and I don't think it will be a disappointment."
Without Jones to call on, Ferguson must find a new way to stifle Real's attacking threat. There are rumours that Wayne Rooney could be sacrificed in favour of a more defensive line-up following the decision to play the England striker the full 90 minutes at the weekend while others were rested.
"If you're preparing for a game of football at our level you have to pay respect to the strengths of the other team which we do for every team - the shape, tactics, who the best players are, etc," Ferguson said today.
"You're doing your job and that applies tomorrow, but we know about the strengths of our team anyway. We know our strengths, our pattern and how to go about these games and hopefully that will help us tomorrow."
Ferguson confirmed that Ryan Giggs will play some part in tomorrow's match in what will be his 1,000th senior competitive appearance for club and country, although it is considered unlikely that the veteran will start.
"Tomorrow he will be involved at some point, whether starting or on the bench I am not sure yet," said Ferguson. "His experience in these occasions will be vital to us."