The other is prop Charlie Faumuina replacing the injured Owen Franks, ruled out of the test at Ellis Park because of a groin injury sustained in Argentina last weekend.
Dan Coles is drafted onto the bench in Faumina's place from the team that beat the Pumas 33-15 at La Plata.
The 32-year-old McCaw has missed the last two internationals because of injury but makes a timely return for what is expected to be a keenly contested battle where his experience at the breakdown could prove decisive.
He had been scheduled to be out for longer after sustaining a knee injury against Argentina early last month but made remarkable progress in training last week and was earmarked for a return by coach Steve Hansen.
McCaw has played three tests since returning from an unusual six-month sabbatical.
World champions New Zealand will successfully defend their Rugby Championship if they stop the Springboks from scoring four tries and winning by more than seven points.
"Playing the Springboks at Ellis Park is a challenge that this team is really looking forward to and one we are very excited about," Hansen said in a statement.
"We know the South Africans will come at us with their physical game but to win the Championship they will have to do that by scoring four tries so we are expecting more ball movement than we have seen in the past.
"So the answer is pretty simple for us - we will have to match their physicality and be very accurate with our execution across the park, both on attack and defensively."
Team: 15-Israel Dagg, 14-Ben Smith, 13-Conrad Smith, 12-Ma'a Nonu, 11-Julian Savea, 10-Aaron Cruden, 9-Aaron Smith, 8-Kieran Read, 7-Richie McCaw (captain), 6-Liam Messam, 5-Sam Whitelock, 4-Brodie Retallick, 3-Charlie Faumuina, 2-Andrew Hore, 1-Tony Woodcock
Replacements: 16-Dane Coles, 17-Wyatt Crockett, 18-Ben Franks, 19-Steven Luatua, 20-Sam Cane, 21-Tawera Kerr-Barlow, 22-Beauden Barrett, 23-Charles Piutau.