Rio Ferdinand has a rather interesting theory on why Manchester United boss Jose Mourinho is so frustrated with Luke Shaw.
|Luke Shaw has made just three appearances for Manchester United this season|
The left-back promised the world when he was signed from Southampton for £30million all the way back in 2014.
But the 22-year-old's career has apparently stalled, and he's struggled for first team football under Mourinho.
Last season the Portuguese questioned Shaw's fitness - a move that was criticised, but one that Ferdinand believes was to try and spur the player into action.
And the former Red Devils legend believes it is precisely Shaw's lack of action in response to the comments that has created "frustration".
"I think Mourinho was just prodding him at the beginning to see what reaction he would get," Ferdinand told BT Sport.
"He wanted a positive reaction and he didn't get that and I think then comes frustration from a manager's perspective.
"Therein lies the problem, he's looking for Shaw to give him that problem with Ashley Young playing so well.
"Who wants to take on the mantle as the best left-back at the club? Because Shaw shouldn't be under any competition at the football club."
Shaw has made just three appearances for Manchester United this season, two in the Carabao Cup and one in the Champions League.
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