Du Plessis fractured his right index finger during the first ODI in Durban that India won by six wicket despite his century.
Markram has only featured in two ODIs so far, making his debut against Bangladesh in October 2017. He has also played 6 Tests.
He led South Africa to Under-19 World Cup triumph in 2014 and has been widely regarded as a future captain. However, Du Plessis' unfortunate injury prompted selectors to fast-track Markram to the hot-seat.
"But at the moment, with both our former captains not around, it was an ideal opportunity for us that here is Markram, lets see what he can offer. We are confident. He wants to do it as well. It just gives us an opportunity to open it up and see what he can offer," Zondi added.
More From This Section
He admitted that Markram will be under a lot of pressure.
"It has been a journey. Yes there will be pressure in terms of understanding his role and also being able to perform as a player. For us, we want to see if he can handle pressure because part of leadership is to be able to adjust and perform under pressure. We hope he has the right skill and the right capability to do so," he added.
"At the moment, we don't want to make any commitment. I think our primary focus for now is this ODI series. We do have a captain in Faf. Markram is going to be stand-in captain for the remaining ODIs," Zondi concluded.