The CBF said in a statement it had accepted a request by Santos to allow them and team mate Rafael to play in the Copa Libertadores quarter-final second leg against Argentine side Velez Sarsfield on May 24.
Brazil face Denmark in Hamburg two days later.
Ganso is seen as a potential playmaker in Brazil's 2014 World Cup team while 20-year-old Neymar is by far the most exciting forward Brazil has produced in the last few years.
The CBF said the Santos trio would travel directly to Washington for a friendly against the United States on May 30.
Brazil also face Mexico in Dallas on June 3 and Argentina in East Rutherford, New Jersey, six days later.