Pace bowler Charl Langeveldt withdrew from the tour to India due to political interference in selection, the South African players' association (SACA) said on Wednesday.
Langeveldt, who is mixed race, had been controversially included in the South African squad instead of fellow fast bowler Andre Nel to satisfy a racial target of six players of colour amongst the 14 players.
The 33-year-old Langeveldt withdrew on Tuesday from the three-Test series, which begins in India on March 26.
"South Africa stands to lose two of its premier fast bowlers, Charl Langeveldt and Andre Nel, because of political interference in selection," SACA chief executive officer Tony Irish said in a statement on Wednesday.
"Charl Langeveldt's request to be removed from the squad to tour India is the desperate unhappiness of a player who knows that he has been selected for this tour for quota reasons."
Irish called for Cricket South Africa (CSA) president Norman Arendse to relinquish his right of veto over team selection.
Bitter infighting broke out within South African cricket in February when Arendse refused to approve the squad initially chosen to tour Bangladesh because it included only four black players.
His veto was eventually sidestepped when CSA chief executive Gerald Majola released the team, leading to a standoff between the country's two leading cricket administrators.
"Any form of veto, interference or involvement in the selection of the Proteas by anyone who is not a selector should be abolished," said Irish. "The players' association recently made that recommendation to Cricket South Africa's Transformation Review Committee.
"The players believe in the goals of transformation, but all of them -- black and white -- are adamant that this should not be achieved by interfering in the selection of the national team."
Langeveldt confirmed he did not feel he deserved his place in the Test squad on merit.
"As players, we all have a good idea of when we are clearly in the running for selection and when we aren't," said Langeveldt.
"You just have to look at Andre's Test record compared to mine and the fact that he has been part of all the Test plans while I haven't played a Test for over two years.
"I have always fought for a place in the team, but I don't want to be put there because of my colour.
"Up to now I have been very happy in my role in the ODI team and I know my value there. I'm quite upset by this now and I'm going to need a bit of time to consider my future."
Nel's future is also uncertain.
"I'm as upset for Langes as I am for myself," said Nel. "We are good team mates and I have a lot of respect for him. We are both passionate about playing for South Africa and neither of us deserve to feel like this. It is hard to just shrug it all off."