AB de Villiers has refused to give assurances over his long-term future in Test cricket and warned changes must be made to ensure top players continue to feature in the longest format.
De Villiers took over as Proteas captain after Hashim Amla opted to step down following the drawn second Test against England at Newlands last week.
The prolific batsman will lead his country in the third Test against Alastair Cook's side, which starts in Johannesburg on Thursday, and the final match at Centurion as South Africa attempt to come from 1-0 down.
De Villiers last month played down talk that he could end his illustrious Test career at the conclusion of the current series, but the 31-year-old said he will consider whether to continue playing in all formats over the coming months.
He said: "There have been a few rumours floating around, and in most rumours there is always a little bit of truth.
"It's not just in the last while; it's for two or three years I've been searching for the right answers, to play a little bit less cricket in one way or another, to keep myself fresh and to keep enjoying the game.
"Every now and then in the past few years I've found myself on the pitch not enjoying myself as much as I should be, and that raises concerns within myself. I've been searching for answers and speaking to people and obviously that's leaked a bit."
He added: "I'm still very committed, to the job [captaincy]. I'm not sure - obviously the two Test matches for now are all I'm focusing on and then there's a nice big break of six months before we play Test cricket again.
"Lots of things can happen before then so I don't want to commit myself too much to everything before that. But for now, I'm as committed as I can be and very, very hungry to make a success of the next two Test matches."
De Villiers also called on the International Cricket Council (ICC) to implement changes to schedules to give players a more manageable workload.
"I think it's a growing concern for the ICC and they've been talking about it for the last few years to find the right structure to keep all the guys fresh," the 31-year-old said.
"Obviously international cricket is the main cricket you want to play, especially Test cricket. It's the main format and we all want to be part of that. There are huge traditions and culture in this format. I believe there are one or two areas where we can improve, and make sure that we keep the guys focus in the right place,
"There are big tournaments going on around the world. Some you can't ignore because financially they make a huge difference in our lives, and obviously you've got to look after that side of it as well. International cricket is the main one you want to play, and one or two things will have to change in order for that to happen."