Atletico's No.1 goalkeeper will need an operation and will be out for three to four months, which will almost certainly rule him out of the Champions League last 16 and the clash with Barcelona on 26 February.

Oblak injured himself in the defeat to Villarreal on Monday after falling to the ground when trying to block a cross from Alexandre Pato. The Slovenian was left in a great deal of pain on the ground and had to leave the field with the help of medical staff.

The goalkeeper's left shoulder came out of place, causing a dislocation. Medical staff inmobilised his shoulder and he was taken to hospital where the injury was later confirmed.

The injury to Oblak means that Simeone will now have to put his faith in Miguel Angel Moya, who coincidentally made way for Oblak in 2013 due to an injury of his own.