The Brazilian was hauled off after 57 minutes during Paris Saint-Germain's match against Ajaccio on Friday, and he will not be available until February at the earliest.
The Brazil international was forced off against the Corsicans after 57 minutes, and is not likely to return to match action until the Feb. 8 clash with Bastia.
"The MRI that was performed today confirms a femoral biceps injury. He will be unavailable for an estimated three weeks at the minimum," a statement on the PSG's official website confirmed.
Friday's 0-0 draw with Ajaccio saw Les Parisiens concede the top spot in Ligue 1 to Olympique Lyonnais, which trails by two points but has a league-best plus-24 goal differential.