With 9 Manchester United players making it to the latter stages of the World Cup, there will likely be opportunities for some of the club's youngsters to impress on pre-season tour.
According to the report, the 17-year-old's father tweeted the announcement on Wednesday evening and then quickly deleted it.
With nine Manchester United players making it to the World Cup Quarter Finals - and ex-U18s coach Kieran McKenna now one of Mourinho's assistants - it seems likely that Garner won't be the only rookie the club's manager will select for the pre-season tour, which begins later this month.
Manchester United's academy is famous for producing talented young players, but which current players could be flying out to the states with the first team?
Here's our top 4 contenders
An intelligent midfielder with great vision, Gomes performs best in the number 10 role and is brilliant with the ball at his feet. In 2017, Gomes became the youngest ever winner of the Jimmy Murphy Youth Team Player of the Year award.
Another previous winner of the Jimmy Murphy Youth Team Player of the Year award, the Dutchman is a fearless winger who can play on both flanks.
The 18-year-old is both a creator and a goal scorer and possesses a great work-rate, which will likely endear him to Mourinho.
3) Callum Gribbin
A right winger, who has can also play number 10, the 19-year-old has a superb dribbling ability and is lethal from dead ball situations.
The boyhood Manchester United fan has been at the club since the age of nine, after rejecting the advances of both Liverpool and Manchester City. He has been called up to train with the first team on a number of occasions.
4) Ethan Hamilton
A dynamic left midfielder who can also fill in at left back, Hamilton is a powerful player with a dangerous strike.
The Scotsman, who followed in the footsteps of Darren Fletcher and joined Manchester United from Edinburgh boys' club Hutchinson Vale, has been praised by coaches in the past for his work ethic - something that will not go unnoticed by Mourinho.
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