India had slipped to third after losing a seven-match home series against Australia 2-4 a few weeks ago.
In individual rankings, South African captain Graeme Smith has the opportunity to put pressure on top ranked Indian counterpart Mahendra Singh Dhoni and second-placed Michael Hussey in the list for ODI batsmen.
An all-out victory for the sixth-placed England would see them rise to third and leave the second-placed hosts fifth.
But if Smith's side manages to win the series 5-0 it will close the gap with Australia to just two points. However, if the Proteas win 3-2, their victory margin will not be enough to maintain second place and they will slip to third behind India.
If Andrew Strauss' side win the series 3-2, it would rise to fifth in the rankings and South Africa would drop to third, again providing India with second place.
No victory scenario can see either team putting any pressure on the current table toppers Australia.
In the Rankings for ODI batsmen, Smith is still the highest-ranked player of either side at the third spot.
Further down the top 20, South Africa's AB de Villiers (fifth), Jacques Kallis (10th) and England's Kevin Pietersen (17th) and Paul Collingwood (18th) will be hoping for a strong series to further secure their places among the top ODI batsmen in the world.
South Africa's Dale Steyn will be looking to work his way up from sixth place in the Rankings for ODI bowlers and put some pressure on the likes of leader New Zealand captain Daniel Vettori and second-placed Shakib Al Hasan of Bangladesh.