Denis Cheryshev has been ruled out for the rest of the season with a knee injury, Valencia have confirmed.
Russia winger Cheryshev, a star at last year's World Cup, will therefore miss Valencia's appearance in the Copa del Rey final against Barcelona next month.
And after helping Valencia down parent club Villarreal in the quarter-finals of the Europa League, he will also be out for their semi-final clash with Arsenal.
Cheryshev, in his second spell at Valencia, has made 27 LaLiga appearances for Marcelino's men this season.
Valencia will now have to decide whether or not to trigger a reported €7million option to buy Cheryshev from Villarreal.
In a club statement, Valencia said tests on Monday found Cheryshev has a "capsuloligamentous injury to his right knee, with a tibial plateau fracture".
Valencia, who have won their last four games in all competitions, are away to Atletico Madrid in the league on Wednesday.
They sit fifth in the LaLiga table, two points outside the Champions League qualification places, with five games to play.