France hooker Benjamin Kayser has been ruled out of the remainder of the Six Nations, after suffering a serious knee injury in the Top 14 clash between his club Clermont and Grenoble on Friday.
The 29-year-old - capped 24-times - partially ruptured a ligament in his right knee, according to Clermont, during the 13-16 loss to Grenoble.
The news will not please France head coach Philippe Saint-Andre, who had pleaded with the clubs not to field players who had started both the 26-24 win over England then the 30-10 victory over Italy.
Several clubs were not happy with the request but Kayser was not one of the players implicated as although he started the win over England he was a replacement for the Italian match.
"Injured at the end of the Grenoble match, Benjamin Kayser suffered a partial rupture of the internal ligament of his right knee," said Clermont in a statement.
"The injury will see him ruled out of action for between five to six weeks and bring to a premature end his interest in the Six Nations."
Among those who could be called up to replace him are Perpignan's Guilhem Guirado, capped 18 times, the uncapped Brice Mach from French champions Castres and Toulouse youngster Christopher Tolofua, capped twice.