Montpellier without Trinh-Duc for Challenge Cup Final
The 29-year-old picked up an ankle injury playing for France in the Six Nations in mid-March.
He made a brief comeback as a late replacement in his club's Top 14 game at La Rochelle at the weekend but will have to sit out the Final in Lyon.
"The choice is difficult, we wanted to offer him this chance, but it's not possible," said Montpellier's South African coach.
He will be replaced by his fellow South African, Demetri Catrakilis.
In other team news Australian scrumhalf Nic White is set to get the call up over Benoit Paillaugue, who is recovering from a shoulder sprain.
This is Montpellier's first ever appearance in a European Final since their creation in 1986.
Club captain Fulgence Ouedraogo said: "We have the possibility of winning a title, to give pleasure to all the team, the club and the city.
"We want to be the first to lift a Challenge Cup, the first to perhaps win the Top 14."
Agence France-Presse