PSG lose defender Thiago Silva indefinitely
Paris Saint-Germain captain Thiago Silva gives instructions during a match against Troyes at the Aube Stadium in Troyes on April 13, 2013.
"The MRI test carried out on Thiago Silva confirmed a muscle tear in the left thigh," read a statement on the club website on Monday.
"The length of his absence will be revealed at a later time depending on the evolution of the injury," the statement continued.
The centre-back was substituted in the 16th minute of the 1-1 draw at Parc des Princes which kept Monaco two points clear of PSG and Saint-Etienne.
"I think we've lost him for some time," said PSG coach Laurent Blanc.
The capital club are in action on Wednesday with an away match at second-from-bottom Valenciennes, while Monaco host Bastia as part of a full midweek programme.