Paris Saint-Germain has confirmed Thiago Motta suffered a broken nose when he was headbutted in the tunnel by Bastia's Brandao on Saturday.
PSG ran out 2-0 winners at Parc des Princes, with Lucas Moura and Edinson Cavani scoring the goals, but the Ligue 1 clash was marred by an incident as the players made their way to the dressing rooms.
Video footage showed Brandao waiting for Motta in the tunnel following the full-time whistle, with the ex-Marseille man appearing to headbutt the PSG midfielder in the face.
Motta, who was then held back by a host of team-mates and club staff, was subsequently shown with a bloodied nose and PSG revealed that what they described as an "assault" resulted in a broken nose for the Italy international.
Paris Saint-Germain president Nasser Al-Khelaifi had earlier called for Brandao to be banned for life.
The club also confirmed that star forward Zlatan Ibrahimovic and Dutch fullback Gregory van der Wiel suffered injuries against Bastia.
Ibrahimovic's diagnosis following his 16th-minute substitution was a strain to his abdominal muscle, while Van der Wiel has suffered a fracture to one of his vertebra after receiving a knee to the back from Brandao.
No timetable has been put on the players' returns, but the news will undoubtedly come as a blow for coach Laurent Blanc.