Garbajosa, 27, will undergo a scan to assess the damage but it is feared that he will be out for as long as eight months. "It is a tragedy for him," said Toulouse coach Guy Noves.
"It is also a blow for the whole team because he is going to miss at least seven French championship games and four Heineken Cup matches if not more."
Garbajosa won the last of his 32 French caps in the World Cup warm up match in August 2003 that ended England's 14-game unbeaten run. He will now miss next month's Tests against Australia and New Zealand as well as more than half of Toulouse's pool matches in the Heineken Cup.