Western Force hooker Nathan Charles has been ruled out for the rest of the Super Rugby season after he injured his knee playing against the Cheetahs.
Charles ruptured the anterior cruciate ligament in his right knee during the Force's 10-19 Super Rugby loss in Perth to the Cheetahs.
The Force hooker is expected to be ruled out of all rugby for up to nine months taking him to the end of the year.
The twenty-four-year-old is the only known professional rugby player with cystic fibrosis and his loss will be a blow for the Force as he has been enjoying good form this season.
Charles' injury could benefit former Rebels hooker Heath Tessmann who is set to be promoted into the starting line up for the Force's match on Sunday against the Waratahs in Sydney.
Ben Whittaker is set to be named on the bench as he has overcome a broken foot but the Force are still sweating on the fitness of injured five-eighth Sias Ebersohn (hip) and prop Pek Cowan (rib).