Blitzboks forward Zain Davids will undergo shoulder surgery on Wednesday, and has been ruled out of the last three tournaments of the World Rugby Sevens Series.
The 22-year-old injured his shoulder during training in Hong Kong last week and had to return to South Africa before the start of the tournament, where the Blitzboks finished seventh.
However, there was good news on the injury front with confirmation that regular captain Philip Snyman and the experienced Cecil Afrika, along with young guns JC Pretorius and Mfundo Ndhlovu, will all be fit for the final two tournaments of the series in London and Paris.
The Blitzboks are in a tight race with England to retain fourth spot on the Sevens Series log, which will give them automatic entry to the 2020 Olympic Games in Japan, and that challenge will continue in Singapore this weekend.
South Africa have been drawn alongside Fiji, who won in Hong Kong, Scotland and Canada in Pool A.