Neymar left Brazil training early on Tuesday after feeling pain in his right ankle and will undergo physiotherapy, the Brazilian Football Confederation said.
The 25-year-old missed an outdoor training session on Monday after feeling pain from Brazil's opening match against Switzerland in which he picked up a knock after being repeatedly fouled.
"He was feeling pain thanks to the large number of fouls he suffered in the Switzerland game," a Brazil spokesman said on Tuesday.
"He complained of pain and so he went to physio and he will train normally tomorrow."
Neymar departed training after just a few minutes in Sochi, leaving his team-mates to continue the session as they prepare for their second World Cup group game against Costa Rica on Friday.
The Paris Saint-Germain forward missed a large spell of the French season after breaking a bone in his foot in February and returned just in time for the Russia tournament.
Source: Skysports