The Dutchman said: "This boy is, as far as his skills are concerned, a super talent. He had his training with Sporting Lisbon. Technically he is so good, he is almost perfect.
"I am convinced he will be one of the big entertainers in this European Championship.
"But I also stress that despite all his talent he may not be right for the Premier League. His crosses are sometimes OK, sometimes bad. And he dribbles too much with the ball.
"He dribbles because he wants to entertain, not because he wants to be effective. Cristiano Ronaldo had the same problem when he first played for Man United, so there is still hope for the boy under United's training regime."