The list includes 15 of the 29 players who were part of the squad for the away leg of the Castle Tri-Nations Series.
The Springbok squad for the home leg of the Castle Tri-Nations series will be announced by electronic media release on Friday.
“Eight of this group have not played any rugby since the end of the Vodacom Super Rugby competition and have been on rehabilitation programmes, with their European clubs or with the Springbok squad,” said Springbok coach Peter de Villiers.
“Our medical team is continuing assessments on the remainder of the players who were unavailable for selection for the away leg. There are still injury concerns around a number of them.”
The eight players who have not appeared since the end of the Super Rugby season are: BJ Botha, Heinrich Brüssow, Elton Jantjies, Zane Kirchner, Francois Louw, Johann Muller, Adriaan Strauss and Coenie Oosthuizen.
De Villiers said the players released back to their provinces and clubs remained in contention for Springbok selection for the Tri-Nations and Rugby World Cup.
Players released are:
Bjorn Basson - Blue Bulls
BJ Botha - Ireland (Munster)
Heinrich Brüssow - Free State Cheetahs
Adrian Jacobs - Sharks
Elton Jantjies - Lions
Zane Kirchner - Blue Bulls
Patrick Lambie - Sharks
Francois Louw - England (Bath)
Charl McLeod - Sharks
Lwazi Mvovo - Sharks
Odwa Ndungane - Sharks
Wynand Olivier - Blue Bulls
Dean Greyling - Blue Bulls
Alistair Hargreaves - Sharks
Ryan Kankowski - Sharks
Werner Kruger - Blue Bulls
Ashley Johnson - Free State Cheetahs
Johann Muller - Northern Ireland (Ulster)
Coenie Oosthuizen - Free State Cheetahs
Chiliboy Ralepelle - Blue Bulls
Deon Stegmann - Blue Bulls
Adriaan Strauss - Free State Cheetahs
Flip van der Merwe - Blue Bulls