Holland coach Ronald Koeman knows Ajax defender Matthijs de Ligt is wanted by Europe's biggest clubs.
Barcelona, Manchester City and Juventus are all chasing the Holland international.
"I just talked with Matthijs de Ligt about the fact that he does not think he is having a sufficient challenge in the Dutch league. I did not know he had said it to the media, but I can understand if he thinks so," revealed Koeman.
"It says a lot about the level of the Dutch league. I can imagine that when you first play in the Champions League and then against Excelsior away, on artificial turf... Then you have to challenge yourself. You expect it from every player, but it's hard.
"The intensity of the Dutch league is much smaller, just like the competition. He can enter any match as it is a final. But the atmosphere, the arena, the plan ... it's completely different."