Uncapped Internacional full-back Geferson has been drafted into Brazil's Copa America squad after an injury to Real Madrid's Marcelo, the Brazilian Football Confederation (CBF) said in a statement.
Marcelo was ruled out of the June 11-July 4 tournament in Chile after suffering a back problem during training, Xinhua news agency reported.
Geferson, 21, is a key member of the Internacional team that has progressed to the semifinals of this year's Copa Libertadores, South America's top club competition.
The Selecao begin their Copa America campaign against Peru on June 14 before also meeting Colombia and Venezuela in the group phase.
Dunga's side will warm up for the tournament with home friendlies against Mexico and Honduras.