MADRID Dec 13 Slovenia international goalkeeper Jan Oblak dislocated his left shoulder in Atletico Madrid's 3-0 defeat at Villarreal on Monday, the La Liga club confirmed.
A club statement said: "The Slovenian was transferred to a medical centre where his shoulder was set."
Oblak was injured while attempting to prevent Jonathan dos Santos from scoring Villarreal's second goal and was replaced in the 40th minute by Miguel Angel Moya.
The 23-year-old will undergo further tests to confirm his expected length of absence.
Oblak has started in 15 La Liga games for Atletico this term and has kept seven clean sheets.
Sixth-paced Atletico, who have won just two of their last seven league games, are 12 points adrift of leaders Real Madrid and host Las Palmas on Saturday. (Reporting by Adriana Garcia; Editing by John O'Brien)