Ghana international Bernard Kumordzi will spend three months on the sidelines after undergoing surgery to correct a fractured tibia.
The box-to-box midfielder suffered the horror injury during Genk's 2-1 win at Mouscron-Peruwelz on Saturday in the Belgian top-flight.
Kumordzi's injury to his left leg happened just after the hour and had to be replaced by Khaleem Hyland.
He had to leave the field with help from Genk's medical team.
The 29-year-old has been one of the key player for coach Alex McLeish in their chase for the Belgian Pro League title.
Genk are expecting to have Kumordzi back in action in December.