McCaw's place will only be assured once he gets through Thursday's training run, but his legendary determination and fitness are likely to ensure that happens.
His knee injury, suffered when prop Charlie Faumuina fell on him during the win over the Pumas in Hamilton three weeks ago, kept him out of the bloody battle at Eden Park a week later and the recent one-sided win over Argentina.
McCaw's sabbatical and injury means this will be only his fourth test of the year and his leadership will be crucial against a team which will be whipped into a frenzy by a capacity crowd and their need to score four tries and deny the visitors a competition point to win the Championship.
Already missing the experience and coolness of Dan Carter at first-five due to his shoulder injury suffered in the fiery first clash in Auckland, the All Blacks are also likely to be without tighthead prop Owen Franks, the Crusaders player having strained a groin early in the match against the Pumas.
Ben Afeaki is scheduled to fly to Johannesburg to cover for Franks, with Afeaki's Chiefs teammate Tanerau Latimer flying home from Buenos Aires after covering for No8 Kieran Read's back injury. Latimer spent only 24 hours in the Argentine capital.
The Boks are likely to be missing at least one of their first-choice players - Flip van der Merwe - after the lock was cited for using his elbow when tackling Wallabies wing Joe Tomane in the home side's comfortable 28-8 win at Cape Town on Sunday.
It was a tackle technique eerily similar to a "fend" used by hooker Bismarck du Plessis against Liam Messam at Eden Park, an act which earned him a second yellow card and his marching orders.
Du Plessis was cleared of any further action which means he will get his chance for revenge - but van der Merwe is unlikely to be as lucky.
The lock's elbow to Tomane's face also had similarities to prop Dean Greyling's assault on McCaw in last year's Rugby Championship test in Dunedin, an act which earned a relatively light sentence of a two-week ban.
The All Blacks last played at Ellis Park in 2004, a 40-26 victory for the Boks in which they scored five competition points and New Zealand none. A similar scenario would earn them the title by virtue of their superior points difference.
New Zealand has won at the ground only three times in 11 tests over 85 years, a history which includes the gut-wrenching 15-12 World Cup final loss of 1995.
All Blacks' record at Ellis Park
Lost 40-26, 2004
Lost 46-40, 2000
Won 35-32, 1997
Lost 32-22, 1996
Lost 15-12, 1995
Won 27-24, 1992
Lost 15-14, 1976
Lost 20-17, 1970
Lost 13-0, 1960
Lost 12-6, 1949
Won 7-6, 1928