Gambhir, who was forced to sit out of the just-concluded Compaq Cup tri-series in Sri Lanka, which India won, due to a groin injury, cleared a fitness test on Thursday afternoon and will leave for South Africa along with the rest of the players from Mumbai on Friday.
Since returning from Sri Lanka, Gambhir was treated for his injury at the NCA under the supervision of physio Paul Close.
Favourites India start their campaign with a high-voltage clash against arch-rivals Pakistan in Centurion, on September 26.
Seeded No 4, India are pitted in a tough group comprising 50-over World champions Australia, Twenty20 World champions Pakistan and West Indies.
The top eight teams will play three matches in the group stages following which the top teams from each group will qualify for the semi-finals.
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