France flyhalf Romain Ntamack faces several weeks on the sidelines, and could miss the start of next year's Six Nations, after suffering a double jaw fracture that requires surgery, the 21-year-old said.
Ntamack suffered the injury in Toulouse's Top 14 victory over Bordeaux Begles on Sunday. He was substituted with around 12 minutes remaining.
"Following a blow to the jaw which occurred in the first half of the match between Toulouse and Bordeaux the examinations show a double fracture of the jaw," Ntamack tweeted.
"I will have to undergo an operation and be away from the field for a few weeks."
Ntamack has formed a formidable partnership with Toulouse team mate Antoine Dupont, the 2020 Six Nations player of the championship.
He is likely to miss Toulouse's trip to Exeter Chiefs in the Champions Cup next month.
France head coach Fabien Galthie will assemble his squad for the 2021 Six Nations on Jan. 25, with 'Les Bleus' facing Italy at the Stadio Olimpico in their opener on Feb. 6.
Galthie's side were second behind champions England on match points difference last season and also suffered a sudden-death defeat by the World Cup finalists in the Autumn Nations Cup final.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Peter Rutherford)
