Robinho could miss Brazil's international friendly against Mexico due to injury, prompting doubts over his fitness in the run-up to the Copa America.
The Santos forward pulled out of training on Wednesday due to a right knee problem, while he sat out Thursday's session as he underwent MRI scans.
The Brazilian Football Confederation (CBF) released a statement revealing the 30-year-old will continue to receive treatment ahead of Sunday's friendly at Allianz Parque in Sao Paulo.
Should Robinho fail to prove his fitness, the veteran will join Diego Alves, Marcelo, Luiz Gustavo and Oscar on the sidelines for South America's showpiece event, where Brazil will come up against Peru, Colombia and Venezuela in Group C.
One player not under an injury cloud is Shakhtar Donetsk midfielder Fred, as Brazil prepare for their penultimate warm-up fixture, with the South American giants to play Honduras on Wednesday, four days before their tournament opener against Peru.
Fred benefited from Gustavo's withdrawal, drafted into Dunga's Copa America squad, and the enthusiastic 22-year-old is determined to help the nation move on from their humiliating 7-1 defeat to Germany at last year's World Cup on home soil.
"It's very bad to lose for 7-1. We were very sad as well as the supporters but they should stick by us," Fred said. "What happened, happened and we must look ahead to the Copa America and they should support us.
"We don't really talk about it, we prefer not to. We are aware that it's very difficult. So we do prefer to be quiet and not talking about what's happening outside here.
"The new generation has to be able to deal with it and work harder in order to forget about 7-1 defeat. It's already in the past and we have to move forward and think about the future from now."
Mexico head to Sao Paulo on the back of an unconvincing 1-1 draw with 10-man Peru on Wednesday.
Miguel Herrera's men, who will feature as invitees at the Copa America alongside hosts Chile, Ecuador and Bolivia in Group A, were outplayed by the Peruvians midweek but managed to share the spoils after Juan Valenzuela cancelled out Jefferson Farfan's second-half opener.
"They pressed us well, but these are the games that make us strong," Herrera said afterwards.
"This was a test, and I will start thinking about our team for the tournament."