Paris - France No.8 Louis Picamoles may play no further part in the Six Nations after pulling a hamstring, the national team said on Sunday.
Picamoles had to come off after just 15 minutes of France's tight 23-21 win over Italy in their six Nations opener on Saturday.
And the national team released a statement on Sunday saying he has a "pulled hamstring in his right leg" and "will miss France's next games and must rest for several weeks".
France's last Six Nations match is at home to England on March 19.
Picamoles, who has 52 caps for his country, will be replaced by Loann Gujon of Bordeaux-Begles in the squad that will prepare for next weekend's clash at home to reigning champions Ireland.
It's a huge blow for France, who began the Guy Noves era with a hard-fought victory against a surprisingly enterprising Italy at the Stade de France.
Picamoles, 30, who will leave Toulouse to join Northampton next season, was the most experienced player in France's starting line-up on Saturday.
He was replaced in the back row by young debutant Yacouba Camara against Italy and the 21-year-old Toulouse flanker may get his first start against Ireland.