Neil Lennon fears an impressive showing from Artur Boruc at Euro 2008 could see hasten his departure from Celtic.
The keeper is believed to be attracting interest from European giants Bayern Munich and Milan, and the Hoops would find it difficult to fend off the duo should they make an official approach.
Boruc is currently preparing to be the last line of defence for Poland at the European Championships, providing him with an international stage on which to display his considerable talent.
Celtic coach Lennon would not be surprised if the stopper attracts further admirers over the summer, and admits that the 28-year-old may become 'impossible to keep'.
"If Artur has a good European Championships, we might get an offer that means he's impossible to keep," Lennon said.
"We want to hold onto our better players but if you get a ridiculous transfer fee offered, it might be too much for the club to refuse.
"Artur has been fantastic. I'm not saying he is going to leave - and we would be delighted if he stayed on - but he might be impossible to keep if he keeps playing the way he has been playing.
"But it's the same for any player."
Georgios Samaras is another hoping to shine in the shop window of Austria and Switzerland, although Lennon is hoping that the Greek striker's transfer valuation will not rocket on the back of his international displays.
Samaras spent a large part of the 2007/08 season on loan at Celtic from Manchester City, and the Hoops are keen to take him to Scotland on a permanent basis.
"If Georgios has a good tournament, his price tag might go up a couple of million as well," said Lennon.
"I hope he plays well - but not that well."
While there will undoubtedly be coming and goings at Parkhead this summer, Lennon is convinced that persuading manager Gordon Strachan to stay is the most important piece of business for the Hoops' board.
"I'd be disappointed if he upped and walked away from what he has built," he said.
"He is building every year and he has more or less built three different teams since he's been here.
"It's a young, vibrant squad we have now and we just need to add a bit more quality to it and we could push a lot of European teams a long way.
"I like his personality and the way he prepares the team and I like his ideas on the game as well.
"He is very meticulous in the way he approaches games and he's a man-manager as well. He feels for the players when things aren't going so well."