Blues scout Guy Hillion was left to question why the 22-year old Frenchman had returned to Stamford Bridge from his loan at Dutch club Vitesse Arnhem while also admitting his bewilderment at why the former Lens youngster hasn't kicked on since arriving in west London.
"Frankly, I don't know why he put an end to his stay with the Dutch club," Hillion told L'Equipe. "It is a huge waste.
"I already said it and I repeat it, he is the most gifted player of his generation. He could have been exceptional.
"But talent is not enough. When you pile on failures and there is trouble in any club where you played, you have to ask the right questions and question yourself.
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