Robertson provided an update on the injuries to Clarke and Blackadder that have kept them out of the second test.
Another big selection call has been made at halfback, with Cortez Ratima making his second test start in place of TJ Perenara, who also moves to the bench.
On the bench, Robertson said having experienced heads like Barrett and Perenara to provide energy in the game was an asset.
Eben Etzebeth returns also to the starting lineup, after coming on from the bench in the first test.
TJ Perenara, 22.

All Blacks v South Africa: Sititi starts, Barrett to bench as Scott Robertson makes four changes for second test