Lyon have confirmed that Yoann Gourcuff is to undergo an operation on his injured ankle.
The France international will have an articular cleaning procedure carried out on Wednesday.
Lyon had hoped the highly-rated midfielder could hold out until after the final round of UEFA Champions League qualifiers in August.
It is imperative that the club make it to the group stage of European football's premier club competition and they need to have as many of their key men available as possible.
They will, however, be forced to cope without Gourcuff, as he is set to go under the knife.
The 25-year-old has made it clear that there is no chance of him being able to play through the pain.
It is expected that he will be sidelined until at least September, ruling him out of the start of the new Ligue 1 campaign and important Euro 2012 qualifiers.