Villarreal defender Gonzalo Rodriguez has suffered a fracture to the left fibula and will not return to action until next season.
The Argentine suffered the problem in Thursday's Europa League game against FC Twente and had to be taken off midway through the second half.
Scans later revealed the extent of the damage, with Rodriguez now facing a lengthy spell on the sidelines.
A recover period of around three months has been forecast and the 26-year-old will therefore play no further part this season.
News of Rodriguez's injury will come as a major blow as Villarreal look to finish the campaign strongly.
They are pushing for a fourth-placed finish in the Primera Liga and will fancy their chances of claiming Europa League glory.
Having beaten FC Twente 5-1 in the first leg of their quarter-final, Villarreal appear well placed to seal a spot in the last four.