François Trinh-Duc will not be ready for Montpellier's Challenge Cup final on Friday against Harlequins in Lyon.
The France fly-half made his return from an ankle injury last weekend in the away defeat to La Rochelle, playing his first game since the Six Nations, but has been unable to recover sufficently enough to be considered for Friday's final.
Head coach Jake White confirmed on Monday that Trinh-Duc would miss out, with Demetri Catrakilis now in pole position to start.
"The choice is difficult, we wanted to offer him this chance, but it's not possible," White told AFP.
Montpellier head into the contest as favourites and captain Fulgence Ouedraogo is hoping the club can make history in their first European final.
"We have the possibility of winning a title, to give pleasure to all the team, the club and the city," Ouedraogo said.
"We want to be the first to lift a Challenge Cup, the first to perhaps win the Top 14."