'Cillessen is one of the best in the world, he should leave Barca'

The 29-year-old has made just three appearances for the Spanish champions so far this season, playing home and away against Cultural Leonesa in the Copa del Rey and also appearing in the Champions League dead rubber against Spurs last week.

A plyer of Cillessen's quality would normally be afforded more game time, but with Marc-Andre Ter Stegen performing miracles on a regular basis between the sticks his status does not look like changing any time soon.

Speaking to Spanish publication 'AS', de Boer urged his fellow countryman to seek a new challenge away from his current employers.

"I would like Jasper to play more. The problem is he has a great goalkeeper ahead of him. He needs to play 25 or 30 games per season," he explained.

"He should find a new club because I think he's in the top 10 goalkeepers in the world. He decided to stay at Barca and be a back-up, but now he will have the chance to leave and he should seriously consider it. It's his decision."

Aside from Cillessen, de Boer also found the time to give his thoughts on Matthijs de Ligt and Frenkie de Jong, who are considered to be two of the most in-demand players in the world right now. 

"They're exceptional players," he enthused. "Various big clubs are following them, They need to be calm and wait until the end of the season.

"They have progressed to the next round of the Champions League and they're improving a lot. I think they're ready to make the step up. Things have changed in modern football. When someone receives and offer of €75m it's difficult for a player and a club to say no."