Villarreal midfielder Ariel Ibagaza is facing up to six weeks on the sidelines with a ruptured muscle.
The Argentine playmaker has injured his right leg and will be out of action for the foreseeable future.
He sustained the damage during Sunday's Primera Liga clash with Athletic Bilbao.
Ibagaza lasted just 16 minutes of that contest before being forced from the field.
Medical reports suggest he will be unavailable to his club for at least a month, forcing him to miss important domestic and European fixtures.
The news has come as a blow to Villarreal boss Ernesto Valverde, but he is hoping Ibagaza will make a speedy recovery.
"Ariel is an important part of the squad and now we have to hope that he recuperates quickly and is back helping us out soon," he said.