Wesley Fofana will miss the Six Nations after the France centre suffered a ruptured Achilles during Clermont Auvergne's European Champions Cup 48-26 hammering of Exeter Chiefs.
Fofana was withdrawn just before half-time in the Pool 5 clash at Stade Marcel-Michelin on Saturday after scoring one of six tries for the Top 14 leaders, who sealed a home quarter-final at a canter.
Clermont coach Franck Azema said the 29-year-old's injury did not look good and the club later confirmed he is set to undergo surgery on his left Achilles.
The powerful Fofana is to meet a surgeon on Sunday and Clermont said he faces a lengthy lay-off, which is a major blow for club and country.
Les Bleus head coach Guy Noves must now consider which centre pairing to go with for the Six Nations opener against defending champions England at Twickenham on February 4.