United have deal in place for the highly-rated Mexico star after prising the 21-year-old from Chivas Guadalajara earlier this season and even paraded him at Old Trafford.
But the club are yet to convince the Football Association in their efforts to secure a work permit application leaving the transfer in the balance.
Held up: Javier Hernandez must wait on a work permit application before his £7m switch to Manchester United is rubber-stamped
It is understood Old Trafford chiefs will cite the 21-year-old as an 'exceptional talent' before the FA panel responsible with administering the process for the Home Office.
Hernandez, nicknamed 'Chicharito', featured for Mexico as a second half substitute at Wembley on Monday in the South American side's 3-1 defeat to England and is certain to play in South Africa at the World Cup.
Rising star: United will hope to convince The FA that Hernandez is an exceptional talent
But the striker, billed as Mexico's most exciting prospect for a generation, has not played in the required 75 per cent of his country's international fixtures in the past two years and United are mindful their application is not guaranteed to be successful.
In order to secure a work permit, United must convince the FA that Hernandez isan elite player who could not be recruited within the European Union for a similar fee.
The club hope to discover the player's fate this week however they may be forced to abandon the transfer as they did with Brazil defender Celio Silva in 1997, when the £2.2million signing was scuppered by a work permit refusal.
Manchester United's new boy Javier Hernandez says hello to the UKHernandez is living the dream after 'incredible' switch to Man UnitedFergie goes for a red-hot Mexican! United sign Chivas striker Hernandez MANCHESTER UNITED FC