Old Trafford chiefs made the Chile forward the highest-paid player in Britain on a reported £505,000-per-week when they prised him away from Arsenal in January on a free transfer.
Jose Mourinho is plotting another major splurge in the close-season to bring his misfiring squad up to his exacting standards, with as many as eight players being tipped to leave the club.
United's executive vice-chairman Ed Woodward recently reported back to Mourinho on where the club are on acquiring some of the names he has put forward, with Shakhtar Donetsk's £50m-rated Brazilian midfielder Fred on the radar.
Sanchez's huge financial package has already been flagged up by some of their prospective targets, having seen United show how deep their pockets can actually stretch.
It is believed the Red Devils find themselves in a similar situation when it comes to renegotiating deals with some of their existing players, with agents holding out for extra on the wages front too.