Deon Fourie has been added to the Springbok squad ahead of the Rugby's Greatest Rivalry series against the All Blacks, with his return to fitness coming at a timely moment given concerns over captain Siya Kolisi.

The 39-year-old, who can cover both back-row and hooker, impressed in the Stormers' defeat to the All Blacks in the tour opener on Friday and will join the squad in Johannesburg on Tuesday. His last Test appearance was in the 2023 World Cup final against New Zealand in Paris — his 13th cap.

Fourie joins the 26 players returning from South America, with Cheslin Kolbe, Damian Willemse, Jesse Kriel and Ruan Nortje also rejoining the group this week.

Kolisi's availability for the four-Test series, which opens at Ellis Park on 22 August, is now in doubt after the flanker sustained a hamstring injury during the Boks' 17-10 win over Argentina in Buenos Aires on Saturday. It is the same hamstring he had previously injured, having already missed the entire Nations Championship campaign in July.

"I hurt my hamstring again, unfortunately. So, I'll go for a scan and see how far it is," Kolisi told ESPN Scrum after the match. "It is really tough, but I can't be sad about it. There is nothing I can do now, other than to go and have a scan and then see how long I'm out for."

Erasmus confirmed the injury but offered some cautious optimism: "He injured his hamstring, the other hamstring. But it doesn't look too bad."