Romain Cabannes will miss the start of the RBS 6 Nations Championship after suffering a facial injury in Biarritz's Heineken Cup match with Parma.
The uncapped centre took a knee to the face accidentally in the second half of last Friday's clash, and tests have since revealed he has fractured his sinus.
He could require an operation and is set to be sidelined for between four and eight weeks.
That would mean he definitely misses France's opening two games, against Italy on February 3 and Ireland on February 11, and he could also be absent for the home clash with Wales on February 24.
Cabannes, who received his first call-up when he was named in Les Bleus' squad for the forthcoming Six Nations, is one of four centres in the 40-man party.
Stade Francais centre Geoffrey Messina could now be called up as cover.
Clermont-Auvergne number eight Elvis Vermeulen is also a serious doubt for the Italy match in Rome after he was ruled out for two to three weeks with an injury to his left bicep.