South Africa have named five uncapped players in their squad for the Rugby Championship.
Engelbrecht, Jantjies and Vermaak were all previously included in the June Test series squad but did not feature in any of the Tests against England.
"Pat and Siya were [also] part of our thinking earlier in the season and have forced their way into the squad with consistently good performances in Super Rugby," said South Africa's head coach Heyneke Meyer.
"It is important for us to build continuity in our squad, which is why we did not make too many changes," added Meyer.
South Africa will face Argentina, Australia and New Zealand in the forthcoming Rugby Championship.