Toulouse could be without second-row Romain Millo-Chluski for up to three months after he picked up a shoulder injury in his side's victory over Lyon at the weekend.
Millo-Chluski was named in Philippe Saint-Andre's first French squad last week but must wait for further medical examinations to discover the full extent of the injury.
"It's too early to know how long exactly he will be out for," said Toulouse head coach Guy Noves.
"We will have to wait for the full examination this week but its disappointing."
The news is a further blow for the French Champions who have lost Gary Botha and Gurthrö Steenkamp to injury in recent weeks.
Toulouse host Connacht in Round 5 of the Heineken Cup this weekend as they look to secure their passage through to the knock-out stages.
