He told the Liverpool Echo: "Jarrad has always had a huge talent and from day one when he first came into the club, he's been impressing the other players and staff members. He had a very good loan spell with us at PSV so to see him do that is not a surprise to me.
To be honest, I have never had any doubts about him. In principle he has everything to become one of the top defenders in the world.
He's tall, he's good in the air, he will always score some goals while also being comfortable on the ball with both feet and fast. The only thing he has to improve now is his experience because he's still very young but playing on a high level.
He's already made it into the England squad. I spoke to Gareth Southgate a couple of months ago when he was at PSV's game against Ajax to watch Jordan Henderson and he told me he was impressed by Jarrad's performances.
It's great to see him fulfilling his huge potential because he's a great kid from a great family with good parents who support him in the right way. I'm very happy for him and also for Everton because he will be a very valuable player in the near future.
Jarrad's advantage is that he can play in different styles. He's now very comfortable playing alongside James Tarkowski who is a player who suits the system that Everton are playing now.
I think Jarrad can also play in a system like Arsenal or Manchester City with a lot of space behind him because he's so fast and he's reading the game quite well for such a young boy. I expect he will have a great, great future both on a national and maybe even international level."