Clermont forward Paul Jedrasiak will be out for "around six months" with a ruptured knee ligament, his club said on Wednesday, and will miss France's tour to New Zealand.
"Paul will undergo surgery next week," the club said on its website, estimating that the lock would return "around the month of November".
The 25-year-old, who has 10 international caps, injured his right knee on Saturday after coming on as a substitute for Arthur Iturria as Clermont beat Toulouse in the final round of Top 14 regular season.
After the game, Iturria withdrew from the France training squad and Jedrasiak was called up in his place. But an MRI at the French rugby training centre at Marcoussis confirmed the severity of his injury.
Saturday's victory changed nothing for reigning champions Clermont who limped to a mid-table finish in a season ravaged by injury.
On their website, Clermont called Jedrasiak's injury "a final blow for the 'yellow and blue' hit hard by injury this season when we had to use 55 players, a new, sad, record."
Lock Paul Jedrasiak will be out for six months and will miss France's tour of New Zealand.