Coach Owen Da Gama has also appointed defenders Kwanda Mngonyama and Rivaldo Coetzee as vice captains.
The trio have swapped places for the captancy role in recent under-23 competitions such as the Caf Under-23 Africa Cup of Nations tournament held in Senegal in 2015 and the Cosafa Castle Cup tournament held in Namibia this year.
“Dolly has grown as a player in the past few months, and don’t forget he captained the side through the qualifiers in Senegal late last year,” said Da Gama.
“When we started with preparations of the Olympic qualification phase, Kwanda Mngonyama was the captain, while Rivaldo Coetzee led the Cosafa Castle Cup squad.
“This shows we have many leaders in the squad but only one player can wear the armband on the day.”
South Africa will meet hosts Brazil at the Maracana Stadium on Thursday.