Villarreal defender Rodolfo Arruabarrena looks set to miss the start of the new season.
The Argentine picked up a knee injury in training earlier this week as the club returned for pre-season.
The injury is so serious that Arruabarrena has been forced to undergo surgery.
Arruabarrena is expected to be sidelined for up to six weeks.
The full back will definitely miss Villarreal's Intertoto Cup campaign as last season's UEFA Champions League semi-finalists look to win a place in Europe.