Neymar sat out Brazil's outdoor training session on Monday after appearing to take an injury knock in their 1-1 draw against Switzerland, according to a report.
The Paris Saint-Germain forward was fouled 10 times as the Selecao were pegged back in their 2018 World Cup opener on Sunday and had to settle for a share of the spoils.
Neymar completed the full 90 minutes against the Swiss but appeared to hobble for parts of the game, and Brazil head coach Tite had admitted that the PSG star was "not 100%" before the match.
According to Sky Sports News, Neymar was joined by Paulinho and Thiago Silva in staying at the team's hotel gym to carry out physical work while the other 20 members of the squad took part in full training.
Brazil play Costa Rica in their second Group E game on Friday.