Lorient president Loic Fery has warned that highly-rated full-back Raphael Guerreiro will not be sold on the cheap.
The 21-year-old left-back, who can also play in midfield, has been linked with Atletico Madrid and Paris Saint-Germain in recent weeks.
Having impressed at the Stade du Moustoir, Lorient could face a battle to hold on to the Portugal international with a figure of 12million suggested as a potential price tag.
However, Fery warned any interested clubs that fee will not be enough to land Guerreiro given the reported valuation of PSG's Lucas Digne or Monaco's Layvin Kurzawa.
"If you look at his effectiveness and statistics, I can not explain why Raphael would supposedly be worth 12m, when I hear Digne and Kurzawa are worth 25 million," he told L'Equipe.
"Nobody is non-transferable, but it must be for the right price."
The former Caen defender made his senior international debut in November against Armenia before scoring the winner in a friendly against Argentina four days later.
Guerreiro also helped Portugal to the final of the UEFA European Under-21 Championship, where they were beaten by Sweden on penalties.