A report in the Independent on Sunday newspaper said the two-times Champions League-winning manager had written a six-page letter to United explaining his strong desire to manage the club and outlining his plans.
Described as a 'love letter' to the club, it is claimed Mourinho even went into detail about how he would be willing to adapt his style to meet United's traditional attacking ethos.
The report emerged on Saturday night and United declined to comment at the end of a day which saw Van Gaal and his team booed off the pitch by supporters at Old Trafford after another sterile performance in a 1-0 defeat by Southampton.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
On Sunday, Mourinho's agent Jorge Mendes strongly denied the claims.
"It does not occur to anyone that a coach like Jose Mourinho can write letters to clubs offering their services. It is absolutely ridiculous and totally absurd," Mendes said on his management company's website, www.gestifute.com.
Mourinho's second spell at champions Chelsea, where he enjoyed huge success until their spectacular implosion this season, ended in December with his confidants suggesting the 52-year-old was keen on a quick return to the managerial fray.
His affection for United and their former manager Alex Ferguson is well documented and Mourinho was linked with the job after the Scot's retirement until the club plumped for David Moyes as successor.
(Reporting by Ian Chadband, editing by Alan Baldwin)
