Montpellier midfielder Karim Ait-Fana could be sidelined for up to six months after suffering cruciate ligament damage.
The 23-year-old picked up the injury in training last week.
Medical examinations have now revealed the full extent of the problem, with it possible that Ait-Fana will not play again this season.
"The verdict after the medical tests is that I have ruptured my anterior cruciate ligament, and I will be out for six months," Ait-Fana posted on his personal Twitter account.
This is not the first time that the Morocco international has taken in a lengthy spell on the sidelines, with an ankle complaint keeping him out for five months last season.
He missed a large chunk of Montpellier's title-winning campaign in 2011/12 as a result and will be unable to help them in their efforts to recover from a slow start this time around.
Ait-Fana is expected to be sent for surgery at the earliest possible opportunity, offering him a greater chance of returning to action before the season is out.