Inaki Williams is likely to be out for two weeks after spraining his ankle during Athletic Bilbao’s 1-0 derby defeat to Real Sociedad on Sunday.
The forward came off worse for wear from a clash with Yuri Berchiche in the 37th minute, and Los Leones’ official website has confirmed that the player suffered a “left ankle sprain”.
Williams underwent tests on Monday to fully determine the extent of his injury, and there are fears he took a blow to both the internal and external ligaments in his ankle.
At the very least, he is now expected to miss Athletic’s Europa League last-16 second leg against Marseille on Thursday, plus the trip to Valencia in La Liga on Sunday.
Speaking after the game, which was decided by Jonathas in the first half, Valverde commented: “The defeat hurts, but I’m very happy with the character shown by my players.
“It was a typical derby, very close. We weren’t successful [with our finishing] and at times we were rather hasty in our game as we attacked with pace but weren’t patient enough.
“It was more a matter of finishing and they took advantage of a counterattack.
“I won’t talk about the referee as I may regret what I say in the heat of the moment.
“Now we must analyse our mistakes and successes and try to improve on them.”
Valverde has also lost Raul Garcia to a one-game ban in the League for five yellow cards, despite only making his comeback from a six-week injury layoff against La Real, but the trainer can call on Xabier Etxeita again after he completed his suspension.