The World's most expensive player might miss Brazil's next game in Russia 2018
He will spend the rest of the day undergoing physiotherapy, the Brazilian Football Confederation said.
"He was feeling pain thanks to the large number of fouls he suffered in the Switzerland game,' a spokesman told reporters.
"He complained of pain and so he went to physio and he will train normally on Wednesday.
overed sufficiently from a broken foot to play in his side's World Cup opener against Switzerland but is continuing rehabilitation on the injury.
And he was accompanied off the training pitch at Yug Sport Stadium in Sochi where he had been working with his Selecao team-mates.
Two members of the Brazil staff trudged off with the 26-year-old when he was unable to continue.
On Monday, Neymar had posted a picture of his foot receiving treatment alongside the message: 'Working hard.'
He broke his foot back in February while playing for the PSG, but updates on social show media that he is still receiving treatment to get it back up to 100 per cent.
The pre-World Cup rehabilitation process was a long and arduous one and it seems the Brazil talisman is not yet up to speed.
PSG's £198m man struggled to make his mark in the 1-1 draw against Switzerland and was dealt with physically by the opposition.