Seamers Shardul Thakur and Mohammed Shami have been recalled to the Indian ODI squad that has been picked for the six-match ODI series in South Africa. Virat Kohli, who who was rested from the team's most recent limited-overs assignment, against Sri Lanka, returns as captain of the 17-member touring party.

Kedar Jadhav, who suffered a hamstring injury in early December and has not played any cricket since, has also been picked. Thakur too had a problem with his shoulder recently, leading to his missing Mumbai's Ranji Trophy quarter-final on December 7 and both players are expected to be on the park very soon to prove their match fitness. "Shardul will be playing shortly. In fact, he will be playing from the first of January," chairman of selectors MSK Prasad said. "Kedar will be playing the T20 matches shortly. Basing on the report we have got from the physio, we have taken this call [to include them in the ODI squad]."

The series begins with the first of six matches in Durban on February 1. Batsman KL Rahul and the senior spin pair of R Ashwin and Ravindra Jadeja continue to miss out after the selectors felt Yuzvendra Chahal, Kuldeep Yadav and Axar Patel deserved an extended run following their good performances in the last few months.

Prasad hastened to add it was not the end of the road for Ashwin and Jadeja, who last played an ODI in June-July. "We keep repeating this. We have been consistent with Chahal and Axar," he told reporters in Mumbai. "With every game game they have been improving a lot. They should be given an extended run since they are doing very well. It is a unanimous decision. When we picked these three boys, we wanted to increase the bench strength in the spin department. Today, we have five-six quality spinners that are aiming for these slots."

When asked about how Ashwin and Jadeja could thrust themselves back into contentions in limited-overs cricket, Prasad said: "We have enough domestic matches. They have played enough cricket and have enough number of wickets under the belt," he said. "[The] only issue is we have tried these guys [the young spinners] and time and again they are winning games for you, so it makes sense to continue with these guys for some time."

Prasad also sympathised with Rahul's omission despite being among the runs in the T20Is against Sri Lanka where he smashed 61 and 89 in the first two matches. However, he is being considered only for the opening spot, and India are already very well equipped with Rohit Sharma, Shikhar Dhawan and Ajinkya Rahane.

"Definitely we were discussing on that point also," Prasad said of Rahul. "The class and the form he is in, it's really unfortunate that he is missing out. Right now, I think those boys who are already there in the squad have done well, so it makes sense to continue. Maybe in times to come, KL will definitely [get a look in]. We will try and see that he will be fit into different options. So, probably after this series we will have to think about that." Asked if the player had a say in where he wanted to bat, Prasad said the player had every right to express his preference, but it was up to the selectors to identify what was good for the team.

Explaining the rationale behind a 17-member squad, Prasad and his panel wanted to try out different players before settling in on a core squad. And on naming it more than a month before the start of the series, he said: "Three points I will like to bring across: announcing one month before helps them to prepare physically or mentally for the demands of the game. The ODI specialists will have sufficient time to prepare. Second point, they may go a bit early to acclimatise. Third point is logistics. Makes it easy."

Prasad identified the limited-overs series in England as a rough deadline for firming up India's core squad ahead of the 2019 World Cup and said new players would be tried out in the T20Is in South Africa. The selectors' aim is to develop specialist squads for each of the three formats. "Probably from England series, that's where we will have a core team," Prasad said. "Maybe we will fix up on a certain number and focus on that. We will definitely pick new boys for T20Is. I would also like to say we are moving towards that direction - specialists for different formats of the game. We are targeting that we should be No.1 in all three formats. We are No.1 in Test format, No.2 in ODIs and maybe No.4 in T20I series. After this T20I series, we don't know, maybe we could go to No.2 spot."

Prasad also more or less confirmed that MS Dhoni would continue to be India's No.1 wicketkeeper going into the World Cup. "I think he remains as the number one wicketkeeper in the World, and day in and day out we have been seeing, even in the current T20 series (against Sri Lanka) the stumping that he does, the caught-behinds that he takes are phenomenal, there is no comparison. I don't see any wicketkeeper, who is even closer to him in world cricket, forget Indian cricket.

"We are grooming some new wicketkeepers in India A tours. More or less we have fixed up [our] mind till the World Cup and after that at later stages we will start grooming some of those wicketkeepers in India A tours. Let me tell you frankly that still those boys are not up to the levels that we have expected. We will still keep giving them chances in the India A tours and see that they are nurtured."

Arun Venugopal is a correspondent at ESPNcricinfo. @scarletrun