Cape Town - Proteas captain Faf de Plessis landed in Cape Town on Friday afternoon with his right arm in a sling as he continues his recovery from the shoulder injury he picked up in the third ODI against Sri Lanka on Sunday.

Fortunately for the skipper, he will not require surgery and he is looking at around six weeks on the sidelines.

Du Plessis had guided the Proteas to an unassailable 3-0 lead in their five-match ODI series after having gone down 2-0 in the Tests, but when he was ruled out for the final two ODIs the South African brains trust had to appoint a new leader.

The logical choices were Hashim Amla and JP Duminy, who both have abundant captaincy experience.

Instead, the rather surprising call was made to give the captaincy to Quinton de Kock.

Proteas coach Ottis Gibson had said in the build-up to the fourth ODI in Kandy on Wednesday that De Kock has an exceptional cricketing mind, and Du Plessis helped explain the decision in more detail at Cape Town International Airport on Friday.

"We felt that when Graeme (Smith) left there was no real opportunities for young leaders in the team to get one or two occasions where they could captain without being the full-time captain," said Du Plessis.

"You can use that opportunity to learn. There are two or three young guys in the team who have some leadership capabilities.

"With guys like Quinton it's more about developing their personalities and character. Someone like Quinton will grow a lot just by getting extra responsibility.

"It doesn't mean that he will be captain in the future or he won't, we just see an opportunity for him to grow as a player."

Aiden Markram had captained in five ODIs earlier in the year against India when Du Plessis was injured, but his form in Sri Lanka has seen him lose his place in the side.

Du Plessis acknowledged that leadership came "naturally" to Markram, while he also identified speedster Kagiso Rabada as another young player who has leadership potential.

The result on Wednesday did not go De Kock's way as the Proteas fell to a 3-run (D/L) defeat in a rain-affected thriller, but Du Plessis is hopeful that the experience of captaining will benefit De Kock in the long run.

"When I do eventually come back hopefully he will be better off for it with a better understanding of what it's like to be a senior player in the team," Du Plessis explained.

"As a player it's easy to just focus on your own game and when you are captain you don't have that luxury, so this will teach him a different side of cricket."

The fifth and final ODI takes place in Colombo on Sunday and starts at 11:00 (SA time).

Duminy, meanwhile, will captain the Proteas in the one-off T20I on Tuesday.