The American family had steadfastly refused to consider such a controversial move since they plunged the club into debt when taking it into private ownership in 2005.
But in the prospectus sent out to potential investors ahead of a £500million bond issue, the Glazers have warned that 'the indenture governing the Notes (bonds) will limit our ability to sell or transfer, but not prohibit us from selling or transferring our training ground facilities and our stadium.'
Up for grabs? The Glazers' prospectus reveals they could sell Old Trafford
The prospectus also reveals that:
The club has none of its own money for new players.
United may have to SELL players to service the debt in the future.
The Glazers may have to refinance AGAIN in the near future.
The club has already drawn down a £36m cash advance on an £80m four-year shirt sponsorship deal that doesn't begin until the summer.
Burden of debt: United owner Malcolm Glazer
Fears about Old Trafford will concern fans the most, however, with many suspecting that the Glazers intend to sell and then lease back United's famous stadium and the state-of-the-art training ground at Carrington.
Ever since the Glazers bought their club, United supporters have suspected that the ground would one day be sold or, at the very least, renamed.
In a section of the prospectus headlined 'risks related to our debt', investors are warned: 'Although in the sale or transfer of any of these properties, the transferee will be required to enter into a long-term lease with us to enable us to continue to have substantially the same access to such property as we currently do, if we sell or transfer either or both of these properties, we will no longer control them.'
It is understood the Glazers are required by law to outline all possible risk to potential investors in the document.
It is also the case that the Carrington training centre is much more likely to be sold as the family have deliberately not secured any of their credit facilities against it, as they have with the stadium.
Nevertheless, industry experts last night stressed that using Old Trafford as security in this latest round of refinancing does not offer the stadium any particular protection against its sale in the future.
As regards Carrington opened 10 years ago it appears its future is in genuine doubt as the document reveals it 'may in due course be transferred to a holding company or affiliate of the Parent. In the latter event, we will be granted a lease'.
Figures show that United have not spent a net penny on player transfers for three years. Manager Sir Alex Ferguson is likely to have to dip in to a new £75m credit facility if he is to spend more than he can raise through sales this summer.
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