Sir Alex Ferguson and his United squad gathered at Manchester airport this morning for the flight to Valencia ahead of their Champions League match on Wednesday.
In a boost at the back, Rio Ferdinand is set to partner Nemanja Vidic in central defence for the first time this season.
On their way: Sir Alex Ferguson and Rio Ferdinand at Manchester airport
Ferdinand's two appearances since recovering from the knee injury that wrecked his World Cup have both been when Vidic has been rested.
But after watching his side concede nine goals in their past five Premier League games, Ferguson could not have chosen a better time to get his first-choice pairing back together.
Meanwhile, the official reason for Rooney's absence from the party which flew to Spain on Tuesday morning was that the striker has failed to recover from the ankle knock he suffered in Sunday's 2-2 draw at Bolton.
Butthere could hardly be a better time for Rooney to step out of the firing line as he struggles to regain his form and confidence amid the fall-out from allegations over his private life.
Ferguson believes his star striker is findingit difficult to cope in the intense media spotlight, while former England boss Kevin Keegan has blamed Rooney for creating problems for himself with his celebrity lifestyle.
Crocked: Rooney will be missing when United take on Valencia on Wednesday
United midfielder Darron Gibson also said yesterday reports that Rooney, 24, had cheated on wife Coleen with prostitutes had taken their toll on the striker.
Gibson told Sportsmail: 'The scandal, if you like, in the papers didn't do him any favours. It probably did put a lot of stress on him. That could be part of the reason why he's not playing well.
'Obviously, he lost his form in the World Cup and it hasn't come back again. But around the training ground he's still the same person as he was last season when he was scoring goals.
Pat on the back: Rooney is greeted by Sir Alex Ferguson after being substituted at Bolton
'I think it's just a slight confidence issue from the World Cup that he's brought back with him.
'Although he's been around a long time he's still a young player at 24. I think with young players form comes and goes sometimes and he's just having a bad patch.
'I don't know why he's stopped scoring now but, hopefully, he will because, if we're going to win the league, we're going to need him to start again. Fingers crossed he does start.'
Rooney scored 34 times in all competitions for United last season, but his only goal this campaign came from the penalty spot against West Ham last month.
Cool it: Rooney had his ankle wrapped in ice after coming off against Bolton
He failed to hit the target again at the Reebok on Sunday and was substituted more than half an hour from the end after receiving a knock to his left ankle.
Rooney did not appear to be in much pain as he jogged off the pitch, and both Ferguson and his assistant, Mike Phelan, were confident after the game that he would be fit to face Valencia in the Mestalla tomorrow.
But United revealed last night that he had not recovered in time for the second Group C tie against the leaders of La Liga, which Ferguson's side can ill afford to lose following their opening draw at home to Rangers.
The England striker will stay at home in Manchester, as will Ryan Giggs, who has been ruled out for two weeks with a hamstring injury.
Rooney's former Old Trafford strike partner Ruud van Nistelrooy believes his ex-colleague needs to block out the problems in his private life and concentrate on his job on the pitch.
'I think that the most important thing for a footballer is that you focus on the game,' said Van Nistelrooy yesterday. 'That's obviously the main thing. In England there is the press that look into other parts as well.
'That doesn't happen in other countries really. You get judged by your performance on the pitch and that's how it should be. You have to live with that if you play in England.
'The players I played with at United were always focused. They still are. He can handle it, he's proved it.'
Dimitar Berbatov has helped make up for Rooney's failings in front of goal this season, but neither striker was able to trouble Bolton on Sunday, with Nani and Michael Owen on target to salvage a 2-2 draw for United.
That was despite facing a makeshift central defensive partnership of Zat Knight and Sam Ricketts, who had previously played at centre back only for non-league Telford and Oxford United's youth team before moving to Bolton.
Knight said: 'Me and Sam coped with them quite comfortably. Rooney hasn't hit the form that everyone expects and wants him to. He's not at the top of his game at the moment.
Headache: Rooney has a lot on his mind
'Everyone knows he's capable of producing a bit of magic so we were glad to see the back of him, regardless of whether he's in form or not.' Ricketts added: 'I've not really played there much at all during my career. I'm a full back really. Having said that, I do enjoy it. It's a new challenge when you have to go up a level and face players like that.
'They might be misfiring a little bit at the moment but we played well. It felt nice to come off the pitch having done well against top strikers.'
The result means United have conceded seven goals in three away games in the Barclays Premier League this season and captain Nemanja Vidic accepts it is not good enough if they are going to win back the title from Chelsea.
The champions' defeat at Manchester City on Saturday gave United a chance to close the gap at the top to one point but they were held for the third away game in a row.
Ferguson's side face Valencia before travelling to Sunderland at the weekend and Vidic said: 'It is hard to explain what is going wrong. A lot of the goals we have conceded have been from set pieces. It is not the true Manchester United.
'It's a big concern conceding so many away goals. We know over the last few years we haven't given away that many. We have always looked strong.
'Our defending has always been our platform. At Bolton there was one goal conceded from a set piece and one came after a corner, which is not good. We are giving teams too many opportunities and they are taking them. It can't happen again.
'We have to be much better in Spain than we were at Bolton. Valencia are in decent form and top of La Liga. That shows how well they are playing at the moment.'
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