Hooker Bismarck du Plessis has been ruled out for the rest of the year with a knee ligament injury.
Du Plessis suffered the injury early in South Africa's 27-6 win over Argentina at Newlands on Saturday.
Bok coach Heyneke Meyer said although it is too early to say exactly how serious the injury is, it appears as if the hooker will be sidelined for seven to eight months.
"I don't want to mention it before I am 100 percent sure but I definitely think that he is going to be out for probably the rest of the year.
"He went for a scan and may have torn ligaments. I do not want to pre-empt anything before the doctors have the final say, but that type of injury normally rules a player out for seven to eight months," he said.
That would rob the Springboks of Du Plessis for home and away Rugby Championship fixtures against Australia and New Zealand, the return match in Argentina next weekend, and November Tests in Ireland, Scotland and England.
It will come as a a cruel blow for the powerful hooker, who spent several seasons in the shadow of former Sharks and Springbok captain John Smit before becoming first choice for his franchise and country this year.
Meyer said that losing Du Plessis so early in the game had made life particularly difficult at Newlands as the vice-captain is one of the most experienced players in the forward pack.
"We definitely missed Bismarck, not just with ball protection but if you look at the pack it is not the most experienced pack around, he is one of our most experienced players and he is the leader there.
"With Bissie out it is a huge blow, especially with Pierre [Spies] out as well, but I think that Adriaan [Strauss] is a quality hooker and he is a good leader as well so I am happy to have him in.
Strauss replaced Du Plessis at Newlands and should start in Mendoza next Saturday with Tiaan Liebenberg, who came into the squad this week for injured Chiliboy Ralepelle likely to take the free spot on the bench.
The Boks are already without other key players like Spies (hand surgery), Coenie Oosthuizen (neck), Ralepelle (knee) - who have all been ruled out by injury since the June series against England. Source: Rugby365