Michalak is a major loss

Michalak suffered ankle ligament damage during his club's victory over Narbonne at the weekend and will be sidelined for at least two weeks.

It is a further blow to the defending champions, who are already without scrum-half Jean-Baptiste Elissalde.

Yann Delaigue will play fly-half and Vincent Clerc may switch to scrum-half, given Sylvain Dupuy's inexperience.

Clerc, capped by France on the wing, replaced Michalak at scrum-half during the match against Narbonne.

"The forwards helped me a lot and Yann was constantly giving advice and talking to me about what options to take," Clerc said.

"If required, I am ready to do it again. I am going to work hard this week so I am ready if needed."