Grant Williams has replaced injured fellow Sharks scrum-half Jaden Hendrikse in the Springboks' Rugby Championship squad, South Africa Rugby announced on Monday.
Hendrikse suffered a fractured leg soon after coming off the bench in a 29-10 victory over Argentina in Gqeberha (formerly Port Elizabeth) last Saturday.
Williams is the third scrum-half from the Durban-based Sharks to be called up by the Springboks this year with Sanele Nohamba part of the initial squad before being released when it was trimmed.
"It is sad to lose a player like Jaden, who was really beginning to find his feet in the system and starting to make his mark in Test rugby," said Springboks coach Jacques Nienaber.
"We are lucky to have a handful of talented scrum-halves in the country, and as coaches we have been impressed with the form of Grant this season."
South Africa have been hit hard by injuries to scrum-halves with normal first and second choices Faf de Klerk (leg) and Herschel Jantjies (hip) unavailable last weekend.
Cobus Reinach, who began the Springboks season last month as the third choice, made his third consecutive start last Saturday.
De Klerk and Jantjies will be available for the rest of the Rugby Championship with South Africa scheduled to play two matches each against Australia and New Zealand.
Australia will reportedly decide early this week whether they can host the remaining nine fixtures of the coronavirus-affected southern hemisphere competition in Queensland.
Should they be unable to do so, the Championship could be moved to Britain and France, South Africa, or scrapped.
South Africa withdrew from the competition last season because the home-based Springboks lacked sufficient game time after a long Covid-induced break from rugby.