Los Che will be without captain Dani Parejo, who must serve a one-match ban, while defender Jose Gaya and midfielder Enzo Perez are both out injured.
Valencia’s Portuguese midfielder Andre Gomes, who is expected to replace Parejo, told his club’s official website: “I’m going to give the best I can to help my club beat Athletic.
“I’m sure whoever plays on Thursday will have the same determination. We all need to be ready.”
Valencia need a win to maintain their push for Champions League football.
They are fourth in the standings, four points adrift of third-place Atletico Madrid, who won 2-0 at home to Real Sociedad on Tuesday.
Sevilla also won at Levante on Tuesday to go level on 61 points with Valencia.
“There are still nine games remaining and they are all important, ” Valencia winger Sofiane Feghouli said. “Everything could be decided in the last day of the season.
“We need to do the best we can to qualify for the Champions League.”
Valencia were held to a goalless draw by Villarreal at home last weekend.
“We are preparing well for this game,” Gomes said. “It’s going to be a big game.
“We need to be focused because Athletic is a very strong team.
“In the Mestalla (stadium), Athletic made life difficult for us and the game didn’t go as we had planned.”
Athletic held Valencia to a 0-0 draw back in November.
The Basque side go into the encounter after seeing their five-match winning run in La Liga end in Saturday’s 2-0 defeat at Sevilla.
The defeat was even more painful as Athletic’s Iker Muniain tore his left anterior cruciate ligament.
The Spanish forward has been ruled out for at least six months.
To further complicate matters for Athletic coach Ernesto Valverde, Spanish midfielder Ander Iturraspe is also unavailable to face Valencia because of a muscular injury.
Athletic have won their last three home league games and are eighth in the standings, 22 points adrift of Thursday’s opponents.