Olivier Magne could miss the whole of France's RBS 6 Nations defence after picking up a foot injury.
The 31-year-old Clermont-Auvergne flanker, who has won 80 caps for his country, suffered a recurrence of the problem at the start of the year.
The injury is set to be operated on, meaning former French captain Magne could be out for the rest of the season and certainly for the RBS 6 Nations that starts in February.
This is very disturbing for him, said club doctor Jean-Pierre Darnaud. The pain is constant. It's as if he has a sea urchin under his foot when he walks.
The back row forward has had injections in his foot but the pain still persists.
He might have to be operated on now which will probably mean he will have to end his season prematurely, said ASM manager Jean-Marc Lhermet.
An operation would rule Magne out for up to four months.