While sources close to the Florida-based Glazer family have insisted that they have no plans to sell, despite the club's £716.5 million debt, a growing supporter-led campaign is aiming to drive the Americans out.
Related ArticlesRooneys' fortune to be laid bareHenry Winter: angel v Red Devil an even contestSky thinking outside the box'Campbell can cope with Rooney,' says WengerFerguson puts his faith in Rooney for explosive encounterSport on televisionHarris said: 'We have been approached [by potential investors] and if we can lend our weight to doing something for the good of Manchester United, and for football, we will.
''There are also one or two other people in senior positions in financial services who have access to capital.
'There is a serious intent on the part of those people who not only have support in their hearts, but the ability to muster that support from their pockets.
'It depends on the Glazers' attitude, but this is an opportunity for them to take money and go. They [the Glazers] are playing with an icon of football, one of the most respected football brands in the world, and it's in danger.'
United supporters have started to wear green and gold, the colours of the club's forerunner, Newton Heath, as a symbol of defiance against the Glazers, and although the Glazers' recent £500 million bond issue proved a success, Harris warns that the club would be at risk if fans stopped attending games.
He said: 'There are clearly rumblings among the supporters and if those rumblings become a revolution and they stop going, the pounds will stop coming. Then there is peril.'
Meanwhile, United insist that the £80million raised by the summer sale of Cristiano Ronaldo is available.
A statement said: 'The cash will be spent on players who are available and who the manager thinks can improve the squad, not to prove to pundits that it exists.'