Brazil's all-time record scorer underwent an MRI scan on Monday which showed he is "making good progress in his treatment" amid hopes that he will be able to play a part for Carlo Ancelotti's side in the United States.
"He will continue to follow the recovery schedule and fitness programme as planned by the Brazil team medical staff," the Brazilian Football Confederation said.
Neymar was diagnosed with a calf injury late last month and has since been in a race to recover fitness for the tournament, with Brazil kicking off their campaign against Morocco in New Jersey on Saturday.
Now 34, the former Barcelona and Paris Saint-Germain superstar has been an integral part of Brazil's last three World Cup campaigns but there was some surprise at his inclusion this time as injuries have prevented him from playing for his country at all since 2023.
Coach Carlo Ancelotti insisted last week that the player, now with Santos, would be ready for either Brazil's first or second game and added that he was "in no rush" to bring him back.