Golden Lions centre Lionel Mapoe and Blue Bulls loose forward Arno Botha have been called up to the Springboks squad in place of the injured Frans Steyn and Jacques Potgieter.
Steyn requires surgery on his injured ankle and Potgieter is struggling with an abdominal strain picked up during a Currie Cup match last weekend.
Steyn will undergo surgery on Wednesday to clean out old pieces of bone fragments in his ankle joint.
"This was discovered after the Springboks' medical team had a number of scans and x-rays done on the Springbok midfielder last week," said Springbok coach Heyneke Meyer.
"Losing Frans is a big blow as he is one of our most experienced players.
"However, it's better that he gets the ankle sorted out properly as he still has a long rugby career ahead of him and can play many more Tests for South Africa.
"Jacques could not train last week and we were hoping to get him ready for selection for this week, but he has not responded as well as we had hoped and subsequently it was decided to withdraw him from the squad as he would not be available this weekend."
Four more players did not take part in training in Johannesburg on Monday, as they are all nursing various bumps and bruises from last Saturday's victory over Australia in Pretoria.
They are Zane Kirchner (hip pointer), Johan Goosen (bruised heel), Willem Alberts (hip) and Jannie du Plessis (knee).
"Seeing that Willem is also not 100% at the moment, we only have three fit loose forwards in the squad and needed someone to provide cover at blindside flank and number eight, which is why Arno is coming to join us," explained Meyer.
"He was part of our Young Guns squad in June as has been in our plans before.
"Lionel has been in great form lately and apart from providing cover in the midfield, he can also be used on the wing if necessary."
Furthermore, Springbok prop Coenie Oosthuizen will consult a specialist in Durban on Tuesday to further examine his neck.
"I've not been completely happy with his neck, as he still showed symptoms after having played in the Currie Cup last weekend," said team doctor Craig Roberts.
"We're seeking another opinion as we need to make the right decision for his career.
"Coenie is a young player and potentially he has a long career ahead of him, so long term we need to make the right decisions and can't put him at risk in any way."