Athletic Bilbao president Josu Urrutia has insisted that any club that wants to sign Fernando Llorente this summer will have to meet his release clause.
The Spanish striker is believed to have a clause of around £29m written into his current deal, which he signed last season.
Any submitted offer lower than that from potential suitors will not be accepted, according to Urrutia.
"He is a key player and we would not accept less, the supporters would not accept this," said the president.
Llorente, 27, has been linked with the likes of Tottenham Hotspur, Manchester United and Barcelona in recent months.