Hoek worked as a goalkeeping coach under Louis van Gaal at Manchester United and is the latest Dutchman to wade into the Van de Beek debate.
He told VI: "It is a big transition, from the Eredivisie to the Premier League.
"But it is not as easy there as in some matches in the Netherlands. I think that we can only actually assess Van de Beek when we are one year later.
"Perhaps this is the run-up to a fantastic career for Van de Beek in Manchester. If not, there will be plenty of other clubs for him. For now I would say: wait and see."