The Blaugrana have been strongly linked with a move for the French central defender but his current club do not want to see him leave on the cheap.
Instead of welcoming bids for Mathieu, Valencia club president believes that the player could instead commit himself to a long stay at Mestalla.
"We want Mathieu to renew his contract. I do not foresee any problems at the last minute," Salvo told reporters.
"If he decides to go, and I do no think that is the dase, then someone will have to come in and meet his buy-out clause.
"Mathieu will stay here for three more seasons."
If Barca do not make a firm offer for the former Sochuax star then they could target Daniel Agger from Liverpool.