Alexis Sanchez was not seen at Manchester airport with the rest of his Manchester United teammates as the squad travelled to the United States to begin their pre-season tour.
The Chilean returned to training earlier this week with the rest of Uniteds players who did not participate at the World Cup in Russia.
But the 29-year-old, who joined from Arsenal in the January transfer window, was not spotted among Uniteds players on Sunday evening as the squad boarded a flight to Los Angeles.
Several United players including Paul Pogba, Romelu Lukaku, Nemanja Matic and new £52 million summer signing Fred are likely to miss some, if not all, of Uniteds tour of the United States due to playing at the World Cup.
But Sanchez has had plenty of rest due to Chiles failure to make the tournament.
Earlier this week, United confirmed that Sanchez is due to complete a full pre-season camp, which includes the clubs tour of the United States, but have not explained why the forward has not travelled with his teammates.
United will begin their pre-season campaign with a match against Club America on July 20.
Jose Mourinhos side will then face San Jose Earthquakes on July 22. United will take on AC Milan on July 26 before playing Liverpool on July 28.
Uniteds final game in the United States will be against Real Madrid on August 1. Mourinhos men will then return to Europe and play Bayern Munich at the Allianz Arena.
New summer signings Lee Grant and Diogo Dalot both travelled with the squad from Manchester, while Mourinho has also included several academy players.
RoShaun Williams, Demetri Mitchell, James Garner, Ethan Hamilton, Tahith Chong, Mason Greenwood and Joshua Bohui will all get the chance to impress on tour.
Man Utd Tour Squad
Goalkeepers: Sergio Romero, Joel Pereira, Lee Grant
Defenders: Antonio Valencia, Chris Smalling, Eric Bailly, Luke Shaw, Matteo Darmian, Diogo Dalot, Timothy Fosu-Mensah, RoShaun Williams, Axel Tuanzebe, Demetri Mitchell,
Midfielders: Juan Mata, Ander Herrera, Andreas Pereira, Scott McTominay, James Garner, Ethan Hamilton, Tahith Chong,
Forwards: Angel Gomes, Anthony Martial, Mason Greenwood, Joshua Bohui
Andreas Pereira has returned from his season-long loan at Valencia and is competing for a regular role under Mourinho.
Daley Blind was also not spotted at Manchester airport as the Dutchman closes in on a move to Ajax.
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