- Tag results for South Africa cricket
Parnell has not played for South Africa in nearly a year and was sidelined with injury in December.
David Miller has scored 3,342 runs in 63 first-class matches, averaging 36.32 with six centuries and 19 half-centuries.
The four-time semi-finalists have famously never reached the final of international cricket's showpiece event, falling at the last four stage in half of their World Cup campaigns.
Faf du Plessis' comments came after Sri Lanka thrashed South Africa 2-0 in the recently-concluded two-match series.
South Africa have not been whitewashed anywhere in the world since the two-Test series in Sri Lanka in 2006.
Du Plessis said he was also banking on Kagiso Rabada to swing it South Africa's way and eventually to step into Steyn's shoes as their foremost attack paceman.
The ICC recently made the ball-tampering punishment harsher for the offenders, extending the ban up to six Test matches or 12 ODIs.
The ICC earlier this week unveiled tougher sanctions for ball tampering and sledging in a bid to improve on-field behaviour in the sport.
South Africa batsman Theunis de Bruyn has been roped in by Surrey for their next two matches of the County Championship Division One.
Young players looking to succeed need to stay focussed, make tough choices: Former South Africa cricketer AB de Villiers
AB de Villiers suddenly announced his retirement on May 23 from all forms of international cricket with immediate effect.
Kagiso Rabada went on to be man of the series when South Africa beat Australia in a controversial four-match series.
De Villiers expressed that he was tired and that others should be given the opportunity to take forward South African cricket.
South Africa fast bowler Dale Steyn's much-sought return is delayed once again as he has been ruled out of the third Test.
Josh Hazlewood helps Australia wrapped up a 118-run win on the fifth day of the first Test against South Africa on Monday.
Australia finished the fourth day one wicket short of victory with South Africa on 293 for nine, needing 417 to win.