Frederic Michalak is a doubt for France's RBS 6 Nations Championship campaign after he was ruled out for up to four months with a knee injury.

The mercurial fly-half ruptured an interior ligament in his right knee during Toulouse's Top 14 clash with Bourgoin on Friday night.

Michalak, who was playing his first comeback game after two months out through injury, must now decide whether to have surgery on his knee.

He said in L'Equipe: "There are two possible solutions. If I do not have an operation, I will be out for three months, and if I do, I will be unavailable for four months."

With France's first game in the Six Nations coming against Italy in Rome's Stadio Flaminio on February 3, Michalak faces a race against time to be fit.

Biarritz's Damien Traille, who usually plays at centre, has been filling in at number 10 for Les Bleus during Michalak's absence.