Since the Selecao's 2-0 victory over Serbia in their opening Group G match, Brazil's talisman has been absent from action in Qatar.
Neymar left that game early due to an ankle injury, making him unavailable for the remainder of the group stage.
Neymar, 30, returned to training on Saturday and shared pictures with the caption, "I feel good, I knew that I would now," on social media. It was also announced in Brazil's pre-game press conference that Neymar will be available if he completes a session on Sunday without incident.
Neymar will practise today, according to Brazil's coach Tite.
"He'll be playing if he practises well. Today is dedicated to a specific workout. If all goes well during practise, he will play.
Tite stressed that the Brazilian medical professionals will make the final decision.
If Neymar made it through the training session without any problems, Tite responded, "We play a price to be the best, we want to be at our most competent but we never put health at risk."
"Neymar's inclusion in the starting lineup is contingent upon the medical staff approving it.
"I like to give it my all right away. As the head coach, it is my job to assume that duty, and I prefer to do so.
Danilo is eligible for selection, while Alex Sandro is not, according to Tite. Alex Telles and Gabriel Jesus, however, are no longer eligible to compete in the competition.