The Springboks suspended their scheduled training session on Monday following a positive Covid-19 test in the squad.
SA Rugby revealed in a statement that lock Lood de Jager returned a positive outcome in scheduled testing and, because of his close contact with a number of squad members, the entire group has gone into isolation.
"The players have been placed in preventative isolation prior to further PCR testing and a review of the testing data by the Medical Advisory Group (MAG)," the statement read.
SA Rugby added that an update would be issued following the review by the MAG and further testing.
The Boks opened their season with a 40-9 win over Georgia in Pretoria over the weekend, with the second Test scheduled for Johannesburg on Friday (July 9).