Lyon midfielder Yoann Gourcuff is facing up to three months on the sidelines with a knee injury, the Ligue 1 club has announced.
"Yoann Gourcuff underwent an MRI on Monday morning which revealed a sprained right knee with an injury to his medial collateral ligament," it read.
"He is expected to spend between six weeks and three months out, depending on how the injury responds."
Gourcuff scored the only goal in Lyon's 1-0 win over Rennes on the opening weekend of the season.
Marseille president Vincent Labrune has described newly-promoted Monaco as a 'foreign club' and warned the Ligue 2 champion it must obey new rules relating to tax if it wants to be welcomed into the top flight.