Sir Alex Ferguson has admitted Wayne Rooney faces a race to be fit for next Sunday's Premiership opener against Fulham.
Rooney has not played since he was sent off in last Friday's encounter with Porto in Amsterdam and has already been ruled out of England's midweek friendly with Greece after failing to shake off a groin injury.
The striker was missing again today as Manchester United wrapped up their pre-season campaign with a 3-0 triumph over UEFA Cup winners Sevilla and Ferguson revealed he could be struggling to face the Cottagers next weekend.
'It is going to be a push for Wayne to be fit,' said the United boss. 'He has a groin injury, which is causing a little bit of bother at the moment.
'It is nothing serious but there is a worry about next Sunday.'
Having opted not to bring in a striking replacement for Ruud van Nistelrooy and with Alan Smith two weeks away from a full recovery from his horror double leg-break, Ferguson could find himself short of options for the visit of Chris Coleman's men.
Cristiano Ronaldo provided the support for first-choice front-man Louis Saha at Old Trafford but it was only after the Portugal winger shifted to the right wing the pair found their scoring touch to put the Red Devils on the road to victory.
Ferguson had better news on the likely availability of Rio Ferdinand and Gary Neville for the Fulham game.
Both men have been cleared to link up with England for training on Monday afternoon and while Ferdinand has more chance than Neville of forcing his way into Ferguson's plans, they are progressing in positive fashion.
'Gary will probably be able to play 45 minutes on Wednesday and Rio should be fit enough for the full 90,' he said.
'In a way, I am quite happy to have the international this week because any time they get on the pitch can only help us, although Rio is in better shape than Gary if we are talking about the Fulham match.'
Ferguson admitted the margin of victory flattered his side as Ronaldo's late deflected effort, followed by David Jones' injury-time strike provided added gloss to a game which rarely raised itself above average.
Less than three weeks before the transfer window closes, the Scot remains in the hunt for midfield reinforcements, although he insists he will not be held to ransom over any of his potential targets.
'There comes a point when you realise you can only take so much,' said Ferguson, who continues to be linked with Villarreal's Marcos Senna and Bayern Munich's England international Owen Hargreaves.
'This close season has driven the point home even more that people are looking at Manchester United like a milch cow.
'Perhaps it is the cavalier amounts of money Chelsea have been spending which has upped the ante because the asking prices these days have soared to ridiculously high levels.
'It is as if the thinking is that if Chelsea can afford such and such, then we can expect Manchester United to pay through the nose as well.
'But it has got to the point where you can only take so much and I want to make it clear that we are not going to be taken for mugs.'