"We have had a few injury challenges on this tour and last week was not a good start, but we have learnt from last week's match,'' said head coach Pieter de Villiers.
"There have been some frank exchanges this week and the players know what is expected from them and that this is their opportunity.''
Mostert joined the squad after being summoned from Paris where he has joined Stade Francais after playing for the Sharks in the Super 15 this season.
He was included in the first 45-man squad De Villiers selected as Springboks coach in 2008.
Van der Merwe flew home yesterday after damaging a rib against Australia, while Aplon was on the same flight after failing to get over back and shoulder injuries.
The team will be captained for a world record 78th time by John Smit in his 104th test.
Team: Patrick Lambie, Bjorn Basson, Adi Jacobs, Juan de Jongh, Lwazi Mvovo, Morne Steyn, Ruan Pienaar, Danie Roussow, Jean Deysel, Deon Stegmann, Alistair Hargreaves, Gerhard Mostert, Werner Kruger, John Smit (captain), Dean Greyling. Reserves: Chiliboy Ralepelle, CJ van der Linde, Ryan Kankowski, Ashley Johnson, Charl McLeod, Wynand Olivier, Odwa Ndungane.
- NZPA