Antonio Lopez has been ruled out for two weeks after being injured during Atletico Madrid's 3-2 victory over Osasuna on Sunday.
Lopez underwent an MRI scan on his right knee this week and the result indicated that he'd suffered a sprain in his medial lateral ligament. This means that he is likely to miss the games against Real Sociedad and Espanyol, according to AS.
The news will be a blow to coach Quique Sanchez Flores who will need all his players available as the club aim to push up the table to secure European football for next season.
However, he will be buoyed by the return of both Sergio Aguero who missed the game with Osasuna through suspension and Fran Merida who has been declared fit after overcoming a slight knee sprain.
Atletico are three points behind Sevilla in the race for the final Europa League spot.