Star playmaker Cecil Afrika, Bernado Botha and debutant Werner Kok will join the Springbok sevens team ahead of the ninth and final round of the HSBC Sevens World Series, the Marriott London Sevens, to be played at Twickenham.
The trio will replace Seabelo Senatla and Justin Geduld, who join the Junior Springboks squad in Stellenbosch to prepare for the IRB Junior World Championship in France later this month, and the injured Paul Delport.
Afrika has been declared fit following a knee strain and comes in for Senatla, while winger Kok will replace Geduld.
Botha last played for South Africa on home soil at the Nelson Mandela Bay South Africa Sevens in December and replaces Delport.
Both Senatla, Geduld and Delport were in fine form as South Africa beat New Zealand to clinch round 8 of the Series in Glasgow, so the loss is a blow for coach Paul Treu.
"We are obviously very happy to have Cecil back," said Treu. "He is a great player and motivates the rest of the team when he is fit and playing. With him fully recovered following his knee strain, it will also be important for us to manage him well with an eye on the Rugby World Cup Sevens in Moscow next month."
Lam and Curry ruled out for All Black Sevens
New Zealanders Ben Lam and Scott Curry have been ruled out of the season finale in London after suffering injuries on day one at the Emirates Airline Glasgow Sevens.
Curry broke a bone in his hand, while powerful wing Lam has a broken foot, forcing coach Gordon Tietjens to send for Matt Faddes, who played in Hong Kong and Tokyo, and Warwick Lahmert, who last played at the USA Sevens in Las Vegas.
At the Twickenham tournament South Africa head Pool A and will play USA, Australia and France in the main 12-team competition. New Zealand line up in Pool B with Wales, Canada and Kenya, while hosts England are the top seed in Pool C but face tough matches against Fiji, Samoa and Argentina.
Scotland, Portugal and Spain will be battling to win back their core team status in an eight-team qualifier.