Former Manchester United assistant manager Rene Meulensteen believes Davy Klaassen has struggled with demands of the Premier League at Everton.
The midfielder moved to Everton last summer from Ajax, but battled to make an impact under former manager Sam Allardyce.
"Klaassen is proof that the step from Ajax, PSV or Feyenoord to the top competitions has only increased," Meulensteen told AD.
"Sorry, but in the Netherlands do we also play in a 'rush rate'? It is not that crazy that Klaassen has had a hard time.
"At Ajax you can play sixty percent in three quarters of the matches and still win. Well, that is different in England.
"That's why I'd rather have seen him at a club like Napoli. In England there is one magic word: intensity. In terms of content, in terms of physical, in terms of conversion. He has to work hard now to still succeed."