Neymar resumed training with Brazil at their World Cup base in Sochi, Russia, one day after leaving the session early with what was said to be pain in his right ankle.
"I trained well, I felt really comfortable. The foot is fine," the Paris Saint-Germain forward said in an interview with the Brazilian confederation's TV channel, referring to his foot and not his ankle.
The forward missed training on Monday and joined his teammates for only 15 minutes on Tuesday, with doctor Rodrigo Lasmar saying it was a precautionary measure after he felt soreness while jogging.
Wednesday's session was closed to the media, but the Brazilian football confederation (CBF) wrote in a statement posted on Twitter and uploaded a video showing that he took part.
Se liga no @neymarjr treinando nesta quarta-feira, em Sochi! Preparação continua para a segunda rodada da Copa do Mundo. #GigantesPorNatureza #Copa2018 pic.twitter.com/Of8qJrnf5C
— CBF Futebol (@CBF_Futebol) June 20, 2018
It is unclear whether Neymar, who reportedly sustained the injury in Brazil's 1-1 draw with Switzerland on Sunday, completed the entire session. He wore a green vest along with other first-team players and the edge of a blue bandage could be seen beneath his right boot.
Lasmar said on Tuesday that Neymar, who was fouled 10 times in the draw, was expected to return to training on Wednesday in preparation for the Group E game against Costa Rica in St. Petersburg on Friday.
Neymar's first season with Paris Saint-Germain ended in February after he underwent surgery on a broken right foot, but he made his return in the warm-up friendlies against Croatia and Austria earlier this month.
Brazil need to defeat Costa Rica, who lost to Serbia in their opener, to strengthen their chances of moving on from the group stage.
🎙 Fala aí, @neymarjr!
— CBF Futebol (@CBF_Futebol) June 20, 2018
Ele treinou, correu, bateu falta, finalizou... Tudo isso para chegar bem no jogo de sexta-feira, contra a Costa Rica! #GigantesPorNatureza #WorldCup pic.twitter.com/QnucmqJG7j
Neymar addressed the upcoming match in the video, saying: "There are high expectations for the second game. We hope to play a much better match than our debut.
"We want to win, we are going into the match to win and play very well."
He added that Brazil boss Tite is preparing the team for the challenge.
"Tite [coach] is telling us about our opponent. The training today was more about us than them, but we are going to analyse everything and define the best way to beat them."