The 2007 World Cup-winner, seen as a certainty for a starting place if fit, was injured in training at his Japanese club last week.
He is one of 15 players receiving treatment as the Springboks gathered in Johannesburg on Monday to start their preparations for the World Cup which starts in September.
Coach Heyneke Meyer put on a brave face but admitted the injuries could disrupt his meticulous planning.
“I'm very excited to get going - it's been a long few months since our last match, but we've worked incredibly hard behind the scenes and done an unbelievable amount of research and planning,” Meyer said in a statement from SARU on Monday.
“It would've been great to hit the ground running with a fit squad, but because of the situation we're in, we will have to use our next five matches before the Rugby World Cup to experiment with our depth and see where we need cover, which could mean players outside the current squad can still force their way in.
“Managing the injured players will be tough and I really hope we can give as many of them as possible enough game time so that they are in peak physical condition for the World Cup.”
Others sidelined are locks Lood de Jager (elbow) and Pieter-Steph du Toit (knee), loose forwards Heinrich Brüssow (arm), Schalk Burger (groin) and Duane Vermeulen (neck), scrumhalf Cobus Reinach (hand), flyhalf Patrick Lambie (neck), centres Jean de Villiers (knee), Jan Serfontein (hip and knee) and Frans Steyn (pectoral muscle), and wing Lionel Mapoe (knee).
Prop Coenie Oosthuizen underwent surgery on his neck last week and has not joined the squad, centre Jaque Fourie will undergo a strict conditioning programme in the coming weeks and loose-forward Willem Alberts was withdrawn from Monday's training session because of an ankle niggle.
South Africa are in Pool B along with Japan, Samoa, Scotland and United States. – Reuters
Original source: Fourie latest Bok casualty