The Stormers flanker replaces tryscorer Heinrich Brussow, who drops to the bench.
Springbok head coach Peter de Villiers has selected an otherwise unchanged XV following an impressive first 60 minutes at the ABSA Stadium.
The only other changes to the matchday squad come on the replacements bench where Villiers has opted for a five-two split in favour of the forwards.
Reserve scrum-half Ricky Januarie is omitted from the squad, with Brussow effectively taking his spot on the bench. First-choice fly-half Ruan Pienaar will provide cover at No9 if required.
Bulls hooker Chiliboy Ralepelle comes into the reckoning on his home ground as he replaces prop Gurthro Steenkamp in the 22 in the final change to what de Villiers hopes will be a series-winning squad.
"We believe in the abilities of our players and we are confident that they will take things up a few notches on Saturday," said de Villiers.
"We are a squad of 22 focused on a common objective, which is to go out and win a Test series against a very good Lions team.
"We know that we will be faced by a Lions team that will be playing to level the Test series and will provide us with a stern test. We must make sure that we are more than equal to the task."
South Africa (vs Lions, Saturday, June 27, Pretoria)
Test caps are in brackets
15 Frans Steyn (28)
14 JP Pietersen (25)
13 Adi Jacobs (22)
12 Jean de Villiers (47)
11 Bryan Habana (47)
10 Ruan Pienaar (28)
9 Fourie du Preez (44)
8 Pierre Spies (20)
7 Juan Smith (55)
6 Schalk Burger (49)
5 Victor Matfield (81)
4 Bakkies Botha (56)
3 John Smit (82, captain)
2 Bismarck du Plessis (22)
1 Tendai Mtawarira (11)
Replacements
16 Chiliboy Ralepelle (3)
17 Deon Carstens (8)
18 Andries Bekker (14)
19 Danie Rossouw (37)
20 Heinrich Brussow (2)
21 Jaque Fourie (43)
22 Morne Steyn (1)
