The Spain international marksman is being linked with a move away from San Mames, despite signing a new long-term deal last season.
His current deal has a €36 million (£29 million) buy-out clause and the club have reaffirmed they would not take a lesser fee.
"He is a key player and we would not accept less, the supporters would not accept this," said president Josu Urrutia.
Many of Europe's top clubs have been linked with Llorente but he is settled and insists his head has not been turned in recent weeks.
"Now I am only focused on the national side, my situation with Athletic has not changed," he said.