Poland's goalkeeping coach Andrzej Dawidziuk believes Artur Boruc should be looking to leave Celtic.
The highly-rated keeper has been with the Hoops since 2005, establishing himself as one of Europe's top shot-stoppers.
He has had his problems on and off the field during his time at Parkhead, but remains the club's undisputed No. 1.
With his reputation having risen considerably over the last three years, he has been regularly linked with a move away from Scotland.
Italian giants AC Milan were believed to have expressed an interest last season, while Newcastle are also thought to be among his many admirers.
As yet Boruc has refrained from pushing for a move away from Celtic, but has now been urged to seek a new challenge by his international coach.
"Celtic obviously believe Artur is one of the best goalkeepers in the world," said Dawidziuk.
"That's why they have kept their faith with him this season, despite all of the events in his life on and off the field.
"If that wasn't the case, Celtic would have replaced him long ago.
"It's clear that Gordon Strachan wishes to keep him. But I really believe that, for the sake of Artur's career, he should play in a bigger, more demanding league.
"If Newcastle make an offer for him, and Celtic accept it, then I think he should take the chance with both hands. He is at a stage where he needs a new challenge."