Paris - Australia international back Matt Giteau will go under the knife on Monday to fix a groin problem.
The 33-year-old Toulon star took to Twitter on Wednesday to announce the news, without specifying how much time he would need to recover.
"Op on Monday.. Not great news but looking forward to finally getting this groin fixed so I can be 100% for @RCTofficial," said the versatile former Brumbies and Force back.
According to some media, the 102-capped Giteau may miss the next three months.
The news is a blow for the reigning three-time European champions, who host Wasps in that competition on Sunday knowing a defeat will almost certainly see them eliminated.
Giteau has been suffering from this groin problem since last spring.
In his absence, though, Toulon could still call on his international teammate Quade Cooper, All Black Tom Taylor or France's Frederic Michalak at flyhalf, while the Top 14 outfit have the likes of two-time World Cup winner Ma'a Nonu, and France internationals Matthieu Bastareaud and Maxime Mermoz to pick from in the centres.