He bowled with rhythm, speed and craft before leaving the field in pain on Saturday, the second day of the first Test here.
Steyn landed awkwardly during his run-up in India's first innings in the post-lunch session.
Significantly, South Africa has strengthened its hold on India in the first Test match. The type of injury normally takes 4-6 weeks to heal, Moosajee added, nearly certainly ruling Steyn out of the rest of the series against India and putting a question mark over whether he can once again regain full fitness ahead of Australia's tour in March. Steyn won't bowl but may bat if needed in this Test match.
Steyn will see an ankle specialist on Sunday, Moosajee said, after which a timeline on his recovery would be clearer. When Steyn was bowling his 18th over, he sustained serious tissue damage to his left heel. After that Steyn went for scans where the extent of his injury was revealed. He couldn't complete his 18th over and was limping slightly as he headed to the dressing rooms at Newlands. "Just feeling very sympathetic for him". It took Ngidi four months to recover and he has only played one first-class match since comeback and took nine wickets for 83 in the game, signaling his readiness for more game-time. He played all those matches against Sri Lanka a year ago in January, and took 4 for 19 in Johannesburg.