Neymar was unable to train with his Brazil team-mates due to a knee problem, the Brazilian Football Confederation (CBF) confirmed.
The Paris Saint-Germain forward hobbled out of training on Wednesday (AEST) and missed the next day's session because of the injury.
The CBF said in a statement that Neymar is still not ready to return to the training pitch.
"Neymar does activity in the gym," the CBF wrote on Twitter. "The player has had knee treatment and will not train today."
Brazil is set to take on Qatar and Honduras in friendlies ahead of opening its Copa America campaign on 15 June (AEST).
Tite's men get up and running against Bolivia and also take on Venezuela and Peru in Group A.