Monaco playmaker Camel Meriem has seen his season ended because of knee ligament damage.
The 26-year-old underwent medical examinations that revealed the extent of the injury to his right knee.
The problem could require surgery and Meriem is expected to be out of action for at least six months.
The news is a further blow to Monaco boss Francesco Guidolin who will also be without Javier Chevanton and Christian Vieri for Sunday's game with champions Lyon.
Chevanton is currently suffering with an ankle problem while Vieri has been out of action after spraining his knee at the end of March.
The Italian striker returned to training on Thursday but Sunday is expected to come too soon for him.