Neymar, who has been out for a month with a right calf injury, trained on the pitch sidelines on Tuesday for the first time since arriving in the United States.
The Brazil Football Confederation (CBF), said Neymar "took another step in his recovery process" with the appearance at Brazil's training groun in Morristown, New Jersey.
The former Barcelona and Paris Saint-Germain forward performed his first running drills and worked out with a member of Carlo Ancelotti's coaching staff, according to footage released by the CBF.
He was called up by Brazil for the tournament despite picking up a calf injury while playing for Santos on May 17, and had not returned to training since.
Five-time world champions Brazil, who drew 1-1 with Morocco on Saturday, play Haiti on Friday before meeting Scotland in their final Group C clash on Wednesday, June 24.
Sources said on Monday that Neymar -- still recovering from a Grade II muscle injury -- repeated the medical examination he underwent a week ago. The results had not yet been confirmed by the CBF.
Brazilian media said the team's medical staff were hoping to have him back fully fit for the knockout stages, meaning Neymar would miss both the Haiti and Scotland matches in Group C.
Neymar, 34, has not played for the senior national team since Oct. 17, 2023, when he tore the anterior cruciate ligament and meniscus in his left knee while playing for Brazil in a South American qualifier against Uruguay in Montevideo.
Since then, he has not worn Brazil's jersey again and has spent around 700 days sidelined, due to injuries, recovery periods, and rest, according to data from the website Transfermarkt.
Neymar was on the bench for Brazil's 1-1 opener draw vs. Morocco, but wasn't dressed in team kit.
"Neymar is working very hard to recover as soon as possible," Ancelotti said before that game on Saturday. "Our expectation is that he will recover and rejoin the group next week.
"When we included him in the roster, we added him for his technical abilities, which are indisputable. But we also want him for his experience and the example he sets for the young players on the team."
