South Africa's selectors have picked uncapped batsman Rilee Rossouw and left-arm seamer Mthokozisi Shezi for this month's three-match ODI series against Zimbabwe in which they will rest they regular pace pack. Dale Steyn, Morne Morkel and Vernon Philander will not feature but will return for the tri-series, which also includes Australia, that takes place immediately afterwards.

Despite the trio's time off, there was no space for Lonwabo Tsotsobe or Rory Kleinveldt, who were both expected to feature in this series. Tsotsobe was recovering from ankle surgery which kept him out South Africa's tour to Sri Lanka and was declared "on track to being fully fit for the Zimbabwe series," by team manager Mohammed Moosajee in June, while Kleinveldt, who had a knee injury, was due to travel with the A side to Australia. No explanation has been provided for why the pair remain benched but they have made way for Shezi, Marchant de Lange and Kyle Abbott.

Shezi is the only one of the new bowlers who has not played an ODI for South Africa. Although he did not feature among the top wicket-takers in the domestic List A competition, he has been part of South Africa's A side. He was their second-highest wicket-taker in the quadrangular series in Australia with 11 scalps at an average of 14.90.

De Lange was South Africa's leading wicket-taker at that tournament with 14 wickets at 21.71 to earn a recall to the national side after an absence of 28 months - a period which has been punctuated with injury. Since his appearances against New Zealand in March 2012, de Lange has suffered from stress fractures which confined him to the physiotherapist's bench for much of the last two seasons. After making small changes to his action, he made a full return last summer and was bowling at speeds of 150kph and slowly ushered back to the international stage through involvement with the A side.

South Africa's second tier team is also where the other new cap, Rossouw has been plucked from. Although the South Africa A side won just two of the six matches they played in the four-team tournament - and both were against the Australian National Performance Squad - Rossouw was the leading run-scorer overall. He notched up 337 runs at 48.14, including a century and two fifties, at a strike-rate of 96.01. He has shown similar promise throughout his career and has averaged 38.00 or above in List A cricket in the last three seasons.

"He [Rossouw] has also been a consistent performer in franchise cricket for some time and his selection is well deserved," Andrew Hudson, South Africa's convener of selectors said. "The message is clear to all our players: if you perform at domestic level and then take it through to SA A level, you will be rewarded."

Rossouw's inclusion may otherwise have been seen as little more than reward for a strong domestic form - as Stiaan van Zyl and Dane Piedt's was on the tour to Sri Lanka - but he may end up as a serious contender for South Africa's World Cup starting XI. The retirement of Jacques Kallis has opened up a spot in South Africa's batting line-up that will have to fill before next year's event.

Faf du Plessis is the leading candidate to take up that position, as he has done at Test level but, after being dropped from the ODI squad last December following a run of poor form, he will know there is no certainty over his spot. Du Plessis will likely have the three ODIs against Zimbabwe to show whether he has regained fifty-over form before South Africa name their squad for the tri-series.

Along with the return of the regular paces, there may also be space for Under-19 World Cup winner Kagiso Rabada, who will travel with the senior squad. Rabada was the leading wicket-taker for South Africa at the U-19 World Cup with 14 wickets from five games, has earned a franchise contract with the Lions and could be fast-tracked like Quinton de Kock was as South Africa search for an x-factor ahead of the World Cup. "We want him to experience and learn from the environment around the Proteas," Hudson said.

The only department where South Africa seem to have completely settled on their options is the spin one. Imran Tahir and Aaron Phangiso are the two spinners, with Tahir likely to start. Ryan McLaren will assume the role as premier allrounder after Kallis' retirement.

South Africa squad for Zimbabwe ODIs: AB de Villiers (capt), Hashim Amla, Kyle Abbott, Quinton de Kock, Marchant de Lange, JP Duminy, Faf du Plessis, Beuran Hendricks, Imran Tahir, Ryan McLaren, David Miller, Wayne Parnell, Aaron Phangiso, Rilee Rossouw, Mthokozisi Shezi