Robinho was dropped from the Brazilian Olympic team today after Real Madrid said a medical examination found the striker has a groin injury.
The Brazilian football confederation criticised the Spanish club and said the decision was a "disrespect to the entity, to football and to Brazilian fans".
Brazil physiotherapist Luiz Alberto Rosan said he knew of Robinho's injury, but the player would have had time to heal before the Olympic tournament.
The 24-year-old was dropped on the day he and his teammates were expected to report for training with Brazil. He was one of the three players over the age of 23 summoned by coach Dunga, and Real Madrid was not obliged to release him.
The Brazilian confederation said that in 2007 it helped the Spanish club by allowing Robinho to delay his release for the Copa America, and that it was a surprise that Madrid did not reciprocate now.
"Unhappily, I can't go with Brazil to the games, but it is Real Madrid's decision and I respect it," Robinho said.
Dunga summoned 21-year-old Cruzeiro midfielder Ramires as Robinho's replacement.
Real Madrid said Robinho's groin injury was discovered when the player arrived for a medical examination and light training along with most of the club's squad.
Robinho's agent, Wagner Ribeiro, said he has never seen the player "so sad".
"He is an extremely happy person," Ribeiro told the UOL Web site. "The last time I saw him like this was when his mother was kidnapped."
Robinho's mother was kidnapped and later released unharmed in Brazil in 2004.
The Olympic gold medal is the only significant football title Brazil has never won.
