Le Mans are waiting on the results of medical tests to determine the seriousness of goalkeeper Yohann Pele's foot fracture.
Pele was replaced after just 17 minutes of the disappointing 2-0 defeat to St Etienne on Saturday.
He had tried to play on after picking up the injury when conceding Gregory Cerdan's opening own goal on the three-minute mark.
Preliminary medical examinations revealed a fracture to the big toe on Pele's right foot.
The Leon-Bollee outfit are currently 11th in Ligue 1, but will now be without their young shot-stopper for the tough game against Lille at the weekend.