Prop Rayno Gerber and loose forward Gerrit-Jan van Velze has been called into the Vodacom Bulls touring squad in Australia.
They will replace Frik Kirsten and Jacques Potgieter, who sustained tour-ending injuries in the Bulls 41-35 win over the Rebels in Melbourne on Friday.
Kirsten broke his hand and will be out for six weeks, while an injured knee will keep Potgieter out for between six and eight weeks.
They will return to South Africa on Monday.
Wynand Olivier injured ribs and is likely to miss the match against the Waratahs in Sydney on Friday.Francois Venter or Johan Sadie is likely to replace him for the Sydney clash.