Gio Aplon and Dean Greyling have been called up to the Springbok squad following injury concerns around Zane Kirchner and Coenie Oosthuizen respectively.
They will join the Springboks in Johannesburg, where they are currently preparing for the second Test against England at Coca-Cola Park on Saturday.
Kirchner injured his knee late in the first half of the first Test in Durban, won by 22-17 by South Africa. He did not play in the second half and following a scan to his knee on Monday morning, it was decided that he would not be considered for the second Test and will be re-examined next week.
Oosthuizen experienced some stiffness to his shoulder / neck area on Monday morning and the Springboks' medical team decided on a cautious approach. He will be sent for a scan in the next 24 hours after which a decision will be made.
Aplon played the last of his 16 Tests as a replacement against Namibia at the Rugby World Cup last year. Both of Greyling's two Test caps came on the away leg of the Castle Tri-Nations last year, against New Zealand and Australia.
"We are not going to risk any player that is struggling with injuries and it was decided to call in replacements for both Zane and Coenie," said Springbok coach Heyneke Meyer.
"Both Dean and Gio were on our official list of standby players and we’re fortunate that both of them have played Test rugby for South Africa before. They have also been in good form in Super Rugby and were two of the unlucky players that did not make the initial 32-man squad.
"They also attended our Planning Camps and should be up to speed with how we want to play. I'm looking forward to welcoming them to the squad."
Kirchner and Oosthuizen will remain with the squad for the time being, while Greyling and Aplon will link up with the squad as soon as possible.