In-form Atletico Madrid goalkeeper Jan Oblak suffered a left shoulder injury against Villarreal in Monday's La Liga action, the club revealed on its official website.
Oblak was hurt when his save on Alexandre Pato's routine shot resulted in a goal for Villarreal, as Jonathan dos Santos snapped up the rebound and propelled El Submarino Amarillo to a 2-0 lead after 40 minutes.
Oblak was replaced by 32-year-old back-up goalkeeper Miguel Angel Moya, who had only featured once this season in a Copa Del Rey first round fixture against CD Guijuelo.
Atletico beat CD Guijuelo 6-0 on the evening to secure a spot in the quarter-finals of the domestic cup.
On this day, Moya conceded a last minute goal courtesy of Roberto Soriano, following an exquisite display of team passing from Villarreal.
The Spanish shot-stopper should get his first La Liga start of the season when Atletico takes on Las Palmas at the Vicente Calderon on Dec. 17.