Lyon are set to be without playmaker Clement Grenier until December after he was ruled out for four months with a thigh injury.
Grenier picked up the problem during Lyon's 6-0 drubbing at the hands of Arsenal in the Emirates Cup last weekend, the 24-year-old collapsing inside his own half with no-one around him.
The latest setback represents another blow for a midfielder who endured a 2014-15 campaign blighted by groin and thigh problems, only making seven appearances in all competitions.
Lyon revealed the extent of Grenier's injury in a statement on Wednesday.
It read: "Injured last Saturday during the friendly match against Arsenal, Clement Grenier has suffered a complete rupture of the rectus femoris tendon of the left leg.
"After consultation with president Jean-Michel Aulas and Dr. Emmanuel Orhant, Clement decided to have surgery by Dr. Bertrand Cottet-Sonnery.
"The operation will take place Friday at the Jean Mermoz Private Hospital in Lyon. His unavailability is estimated at four months."
