Uncapped scrum-half Piet van Zyl was called up Sunday to replace the injured Jano Vermaak in the South Africa squad.
The Springboks are competing with Italy, Samoa and Scotland in a four-nation tournament, with the second round scheduled for June 15 in Nelspruit.
Van Zyl has sparkled for Super 15 surprise side Central Cheetahs this season, scoring two tries in a recent triumph over the Queensland Reds of Australia.
New cap Vermaak, 28, of Northern Bulls retired 60 minutes into Saturday’s 44-10 triumph over Italy in Durban with a serious hamstring injury.
Fellow Bull Francois Hougaard and Ruan Pienaar from Irish province Ulster are the other scrum-halves in the Springbok squad.
South Africa top the table after a bonus-point victory over Italy with Samoa second thanks to a 27-17 win against Scotland.
Scotland – who were losing to Samoa for the first time – were hardest hit by injuries with a decision due Sunday on whether captain Kelly Brown, Pat MacArthur and Euan Murray can continue to tour.
The departure of flanker Brown, hooker MacArthur and tight-head prop Murray would be a massive blow for the already depleted Scots.
They lost loose-head prop Ryan Grant on the eve of the Samoa Test to the injury-hit British and Irish Lions squad touring Australia.
The three-week South African tournament concludes on June 22 in Pretoria with matches for first and third places.
Springboks call-up for Van Zyl
