The Chile international had been held up by problems relating to his acceptance of a 16-month suspended jail sentence for tax fraud in Spain earlier this year.

But Sanchez is now poised to join his team-mates in a major boost to Jose Mourinho, who is braced for potentially damaging International Champions Cup clashes against AC Milan, Liverpool and Real Madrid.

The Portuguese is still without several World Cup participants including Paul Pogba, Romelu Lukaku and Marouane Fellaini, while England quartet Phil Jones, Ashley Young, Jesse Lingard and Marcus Rashford likewise remain on holiday.

Mourinho has warned results could get ugly, although he insists the prospect of heavy defeats does not concern him.

"AC Milan come with all their players because Italy didn't go to the World Cup," the Red Devils boss told MUTV.

"Then Liverpool, I think everybody is here apart from the English ones. [Jordan] Henderson and [Trent Alexander-]Arnold, maybe not them, but everybody else is. 

"With Real Madrid, Spain were knocked out at a very early stage, so everybody is here too. [Gareth] Bale and [Karim] Benzema didn't go to the World Cup, so we are going to face teams with obviously different potential than us.

"I'm not worried about that – I'm not worried if we lose, even if we lose to some not beautiful numbers."

United's five-match tour begins against Liga MX side Club America on Friday (AEST), three days before a meeting with MLS outfit San Jose Earthquakes.