Wayne Rooney will only join England's World Cup quest if he is fit enough to do himself justice.
Sir Alex Ferguson has outlined a recovery programme for the Manchester United star that will include the use of an oxygen chamber before he goes for further scans later this month which will determine whether he can join Sven-Goran Eriksson's squad in Germany.
Both United and the Football Association have been keen to stress there is no conflict of interest between club and country as far as Rooney's participation in this summer's finals are concerned.
However, while Eriksson continues to insist he would be happy to have Rooney on board even if he was only able to play in the latter half of the tournament, Ferguson is adamant the 20-year-old will not put his long-term fitness at risk by rushing his comeback.
'If he goes, he needs to be fit because otherwise he may not do himself justice, which would be an even bigger disappointment for England fans,' said Ferguson.
'You can't put a deadline on it because the scans will tell us everything.
'In a few weeks' time we will send him back for a scan.
'If the injury has healed we have got the progress we want. If it has not healed there is nothing you can do about it.
'We just have to carry on with the treatment because we are really in the hands of how Wayne improves and we are not going to do anything that will jeopardise the boy.'
Earlier this week Ferguson suggested Rooney had little chance of making the World Cup and cautioned against the rising expectation fuelled by Eriksson's bold statements.
Even now the Scot remains dubious about Rooney being available for anything other than United's pre-season campaign, citing the recovery time for a large number of similar injuries the Old Trafford medical staff has had to deal with as evidence for his theory.
'Gary Neville ended up needing pins inserting because he had not recovered properly,' said Ferguson.
'It took Roy Keane 10 weeks from breaking his metatarsal to being fit enough to play again, while Wayne was out for 14 weeks after doing his for the first time at the European Championship.
'The only one who came back quicker was David Beckham, but he made the mistake of joining up with England in Dubai before the World Cup when he would have been much better staying here.
'In the end, I don't think he was fit enough to go.'
United doctor Mike Stone will continue to plot Rooney's progress, although Ferguson has confirmed Eriksson will receive weekly updates and has made it clear if the Swede wants to send his own staff to United's Carrington training complex, they will be welcome at any time.
'There is an open dialogue between ourselves and England,' said Ferguson.
'They will get an update every week on how he is doing and if they want to send a physio or a doctor up they are free to do so.
'As I have said all along, we will do our very best to help Wayne get there. It is in our interests, as well as England's to do that.'