Tony Pulis says you have to be “very careful” over buying players from the Eredivisie after Chelsea confirmed the signing of Hakim Ziyech.
The Blues must now seal personal terms with the Morocco winger, who will join Chelsea on July 1 for an initial fee of £33m.
Both Chelsea and Ajax confirmed the deal, with Frank Lampard securing his first signing as Stamford Bridge boss.
Lampard and Chelsea were unable to make any headway on recruitment in the January transfer window, leaving the manager frustrated not to bolster his squad.
But Pulis has a warning for Lampard and Chelsea over their latest purchase.
“Dutch football is not Premier League football.
“For all what he’s done and what he’s achieved and if they’re spending that much money you hope and pray that you get it right, but there’s different levels and there’s different levels in respect of the European leagues.
“The Dutch league is a good league, Ajax were fabulous last year and they’ve been good this year, a good group of players and they’ve been unbelievable in respect of bringing good players through.
“But the Premier League is a different animal to the Dutch league.”