Lock Bakkies Botha and centre Jaque Fourie have been ruled out of the remainder of the Tri-Nations series as South Africa prepare to face New Zealand in Cape Town on Saturday.
"Following the match (against Argentina on Saturday), Bakkies Botha had a scan and he has ruptured his posterior cruciate ligament in his left knee," Springbok team manager Andy Marinos said at a news conference today.
"We will adopt a conservative management process which means Bakkies will not undergo surgery but will rather complete a rehabilitation process."
"Fourie had a head clash with the Argentina wing. A scan has shown he has a depressed fracture of his cheekbone and he will undergo surgery before the end of the week which means he will be out for six weeks, post-surgery," said Marinos.
"Both players will be unavailable for the remainder of the Tri-Nations and we hope that Bakkies will be ready in time for the end-of-year tour to the UK."
Botha hobbled off the field with a knee injury in the final minutes of the first half of South Africa's record 63-9 victory over Argentina.
Fourie took to the field in the second half but his first spell with the Springboks this year was limited to six minutes. The centre left the field at the end of the third quarter after a clash of heads with Pumas winger Jose Maria Nunez Piossek.
Bulls lock Danie Rossouw, who last featured for South Africa against Wales in June, has been recalled in an attempt to replace the uncompromising physicality of Botha in the second row.
The versatile Francois Steyn returns from a week of duty with the Sharks in South Africa's domestic Currie Cup competition to fill the void left by Fourie.
South Africa host the All Blacks at Newlands before playing consecutive matches against the Wallabies in Durban and Johannesburg later in August.