Fast bowlers Anrich Nortje and Kagiso Rabada return for the matches at Willowmoore Park in Benoni on Friday and The Wanderers in Johannesburg on Sunday.
The hosts must win both to stay on course for the top eight in the World Super League or they could face the World Cup qualification tournament in Zimbabwe in June, from where the remaining two teams in the field will earn their spots in India.
"We have named our strongest possible squad for these games given the importance of these matches in the context of qualifying for the Cricket World Cup. We have a job to do and I am confident that with this group of players we can get the job done," new white ball coach Rob Walter said.
South Africa lost to the Netherlands at the Twenty20 World Cup in Australia last year in a shock elimination.
South Africa squad:
Temba Bavuma (captain), Quinton de Kock, Bjorn Fortuin, Reeza Hendricks, Marco Jansen, Heinrich Klaasen, Sisanda Magala, Aiden Markram, David Miller, Lungi Ngidi, Anrich Nortje, Wayne Parnell, Kagiso Rabada, Tabraiz Shamsi, Rassie van der Dussen
