Ghanaian defender Emmanuel Ntim is set to spend a month on the sidelines after picking an injury on his Caen debut.
The 26-year-old was forced off just few minutes after scoring in the game against Guingamp over the weekend.
Ntim picked up a groin injury and will be out for four weeks.
Meanwhile, Ntim scored the first goal as Caen recorded a resounding 4-1 win over Guingamp in the round four fixture at the Stade Michel d'Ornano.
The hosts levelled the scoring in the 18th minute when the Ntim connected a pass from Romain Thomas. The visitors took the lead in the 6th minute through Maxime Barthelme.
Guinea Bissau international Alexandre Mendy scored a minute later to put Caen ahead for the first time in the game.
French forward Samuel Essende extended the lead seven minutes after the break before Benjamin Jeannot converted a penalty in the 76th minute to seal the victory.
France-born Ghanaian midfielder Godson Kyeremeh was introduced in the game in the 69th minute, taking the place of Mendy.