Montpellier fly-half Aaron Cruden has been ruled out for a month with a torn calf sustained in Saturday’s 55-13 defeat to Lyon.
Cruden, who was making his comeback after two weeks on the sidelines, sustained the injury in the warm-up, but still played an hour of the match.
The 29-year-old will miss three consecutive Top 14 games, against Toulouse, Perpignan and Toulon, but coach Vern Cotter said he should return in time for the start of the Champions Cup.
“He hurt himself during the warm-up in Lyon, but he played for an hour. In principle, he will be ready for the start of the European Cup,” said the coach.
Montpellier meet Edinburgh in their opening game of the European showpiece on October 13.