Atletico Madrid have revealed that Augusto Fernandez "suffered a complete tear of the anterior cruciate ligament in his right knee" during Sunday's La Liga clash with Deportivo La Coruna.
The 30-year-old was stretchered off the field in the 14th minute at the Vicente Calderon and it was feared after the match that the Argentine had suffered a serious problem.
The severity of the injury has now been confirmed via a statement from the Spanish giants, with Fernandez facing the possibility of missing the rest of the season as he prepares to undergo an operation.
"Tests have revealed Augusto Fernandez suffered a complete tear of the anterior cruciate ligament in his right knee," read a statement on Atletico's official website. "He will be operated upon soon."
Fernandez missed a chunk of last season with an injury to his left knee.
