Valencia may dismiss manager Pako Ayestaran if the club do not get a positive result at Athletic Club on Sunday.
Super Deporte report that the club's hierarchy will look into a managerial change should they lose in Bilbao, after losing their opening three league matches.
The club are losing faith in the man who replace Gary Neville in March, with the club falling to defeats against Las Palmas, Eibar and Real Betis.
Valencia's Director of Football Garcia Pitarch was in the changing room after the Betis defeat and was present at the club's training ground on Monday, signs that Ayestaran is under pressure.
The paper reports that Pitarch held an emergency meeting with president Chan Lay Hoon to discuss the manager's future.