The South African Rugby Union announced that the 21 would remain at home in order to recovery from injuries and to focus on their individual preparations for this autumn's World Cup.
The list of absentees reads like a who's who of Springbok rugby, with Victor Matfield, Schalk Burger, Bakkies Botha, Tendai 'Beast' Mtawarira, Bryan Habana, Fourie du Preez, Frans Steyn and Jaque Fourie all unavailable for those two internationals.
Also on the list are fellow first-team squad regulars Juan Smith, Bismarck du Plessis, Andries Bekker, Jannie du Plessis, Gurthrö Steenkamp, Jean de Villiers, Butch James and JP Pietersen.
"Some players have had a huge a huge amount of rugby and it shows in the wear and tear on their bodies," said former Wales centre Andy Marinos who is manager of national teams at the South African Rugby Union.
"We're treating them on an individual basis to make sure they are fully fit to peak at the right times this year."
The Bok management have not ruled out some of the absent stars playing some part in home leg of the shortened Tri Nations but they are remaining tight-lipped on when each of the individuals named will be back in action.
"Schalk Burger and Duane Vermeulen recently sustained serious injuries and will definitely not be ready to take part in the Tri Nations but we're hopeful that others who have had long-term injuries, such as Juan Smith, Heinrich Brüssow and Gurthrö Steenkamp, may be available at some point in the series," added Springbok team doctor Craig Roberts.
"There are a number of other players who have been playing through Super Rugby with chronic injuries and need rehabilitation now to avoid the risk of the breaking down with longer term injuries in the near future."
South Africakick off their Tri Nations campaign against Australia in Sydney on July 23 before travelling to New Zeland to take on the World Cup hosts in Wellington on July 30.
They then host the Wallabies in Durban on August 13 before finishing up against the All Blacks in Port Elizabeth a week later.
Injured players unavailable for selection for South Africa's away leg of the Tri-Nations
Duane Vermeulen (knee), Fourie du Preez (knee), Schalk Burger (thumb), Victor Matfield (calf and neck), Frans Steyn (ankle and back), Jaque Fourie (groin), Jean de Villiers (groin), BJ Botha (knee), Juan Smith (Achilles), Willem Alberts (shoulder), Bismarck du Plessis (shoulder), Andries Bekker (shoulder, groin and ankle), Jannie du Plessis (knee), Francois Louw (clavicle), Gurthrö Steenkamp (forearm), Francois Hougaard (ankle), Butch James (knee), JP Pietersen (back), Tendai Mtawarira (hamstring), Bryan Habana (shoulder), Bakkies Botha (knee)
The Springboks will name their squad for the away games against Australia and New Zealand this Saturday.