The South African flanker Duane Vermeulen has become the latest Springbok casualty ahead of three tests next month after suffering a knee injury at the weekend.
He faces a lay off of up to eight weeks after a medial collateral ligament injury playing for the Stormers in their Super Rugby loss to hosts Waratahs in Sydney.
Vermeulen suffered similar serious knee injuries at the same stage of the last two seasons.
South Africa are already without flanker Schalk Burger and backs Johan Goosen and Francois Steyn for the home series.