Lyon are set to be without Fabio Santos for the start of the Ligue 1 season after the Brazilian midfielder fractured his cheekbone during a friendly against Nancy on Thursday evening.
Santos, who has just returned from a six-month loan spell with Sao Paulo in Brazil, clashed with Nancy's Moncef Zerka in the first half of the 3-0 win.
He was taken to hospital and is set to remain there overnight for observation.
Coach Claude Puel confirmed the player can expect a long spell on the sidelines.
He told the club website www.olweb.fr: 'We'll lose Fabio for several months as he has suffered a fracture of the cheekbone. It's a real shame.'