"If you see, Gautam is definitely the third opener that we are considering. As of now, Murali Vijay and Shikhar Dhawan, they have done really well for us. So third opener as of now is Gautam," Dhoni said.
"I know (Gambhir is not part of the team) but he is the third opener. But you never asked if he is part of the team," Dhoni added before India left for their African Safari.
Dhoni also said that it was not decided who will replace Sachin Tendulkar at No.4 in Tests.
"We are not decided on No.4. No one is going to replace anyone else. If possible, we will omit the number 4. And try to bat 1, 2, 3, 5, 6... And 12," said Dhoni.
The skipper also said it will be a fresh start for Indian cricket as the team embarks on a tour to South Africa without the Master Blaster, who retired from all forms of cricket last month.
Dhoni said the three-match ODI series that starts the tour will help the team prepare well for the two Tests.
India will first play the ODI series in Johannesburg (Dec 5), Durban (Dec 8) and Centurion (Dec 11).
The only practice match, a two-day affair, is slated for Dec 14 and first Test starts Dec 18 in Johannesburg and the second from Dec 26 in Durban.
"If you see, there is always a new start," Dhoni added.
He said it will be a new challenge for his young team.
"Many of them have had good exposure if not in Tests, but in ODIs. It is a new challenge for all of them and a new learning curve. It is always a challenge when you go outside. Which length to bowl and to adjust to the bounce of the wickets. It is good to start with ODIs. As the batsmen can play their shots and express themselves and carry it into the Tests," Dhoni said.
Dhoni also hoped that the bowlers will perform better in the death overs unlike what they have done in the series against Australia.
"In different conditions the statistics would be different. There will be pace and bounce on offer for the fast bowlers. Along with the yorkers, they can use bouncers and a little bit pace. So we will see how it goes," he said.
The India captain said bowlers have improved a lot while bowling in the death overs, but expects a lot more from them.
"In the last few matches it has improved a lot but we are trying to see how to improve (more), so that we don't give lot of runs in the last 10 overs. If you see our Champions Trophy performance and if you compare our death (overs) bowling you will see that it is a completely different scenario. The ideal would be to compare how the Indian bowlers performed in the last 10 overs and how Australian bowlers performed in the death overs in the same game. Then it becomes more realistic," he said.
Dhoni said it would be a good series between the two top Test nations.
"If you see both the teams are well positioned in the rankings. In ODIs it is us and in Tests it is them. It is going to be an exciting and interesting series. The key is getting adjusted to conditions as early as possible," he said.
"They have a very good team, a well balanced team, with genuine all-rounders. Pressure goes hand in hand whether we play in India or away," he added.
Dhoni also said that the team management is yet to decide whether they will go in with five specialist bowlers.
"We have to see the strength of our batting line up. At the same time, whether four bowlers are good enough to get the opposition out. If you see, at times five batsmen are not enough, even six are not enough. And if you see the last two Test matches, the number six batsman has had a lot of impact on the game. We will weigh how it is and then decide," he said.