Kallis' injury must be significant considering South Africa have a series lead to protect and that he played through the pain of a side strain in the deciding third test against India at Newlands in Cape Town last season. He scored 161 and 109 not out to prove what we already knew: the man is not human, in the most impressive way.
This is something South Africans acknowledge warily. We know that Kallis will one (catastrophic) day retire. Rumours of his mortality we neither want nor need.
In purely academic terms, the removal of Kallis from the equation means South Africa are denied the talent, skill and experience of a player who could hold down a place in any team on the planet.
In his pomp, he could have done so as a batsman or a bowler. Kallis no longer bowls long spells, but he can still fetch a vicious over or two from memory. Last season, at Centurion, he pelted Sri Lanka's Dilhara Fernando - who had earlier committed the stupidity of hitting Kallis on the head - with a fearsome over featuring five deliveries clocked comfortably over 140km/h.
Kallis is famously impervious to pressure. Shane Warne tried to get into his bulletproof head in the Boxing Day test of 1997. Kallis was playing his seventh test, Warne his 62nd. Warne took six wickets in the match, but he didn't get Kallis - who scored 101 in the second innings.
Now he is not there, and we are disturbed by his absence. Inside the heart of every cricket-minded South African there is a Kallis-shaped vacuum. And we know that he, too, must pass.
Telford Vice is a freelance cricket writer in South Africa.