Neymar removed his footwear to display a heavily swollen right ankle after being substituted near the end of Brazil's win over SerbiaFifa World CupHost nation: Qatar Dates: 20 November-18 December Coverage: Live on BBC TV, BBC iPlayer, BBC Radio 5 Live, BBC Radio Wales, BBC Radio Cymru, BBC Sounds and the BBC Sport website and app. Day-by-day TV listings - Full coverage details
Neymar appeared to be in tears on the bench at the end of Brazil's opening World Cup win over Serbia after being substituted with a sprained ankle.
Brazil's team doctor confirmed the forward suffered the injury and that it will be reassessed on Friday.
The 30-year-old was replaced in the 80th minute of Thursday's 2-0 win after a heavy tackle from Nikola Milenkovic.
He sat with his face covered while receiving treatment and pictures showed his right ankle was heavily swollen.
"Tomorrow [Friday] we will have a new assessment," said team doctor Rodrigo Lasmar. "Now we need to wait, we cannot make premature comments."
The Selecao face Switzerland in their second Group G game on Monday (16:00 GMT).
The Paris St-Germain striker has suffered a number of injury problems with his right foot over the past few years.
Neymar was fouled nine times during the game, drawing four more free-kicks than any other player at this year's World Cup so far.
Neymar appeared to be in tears on the Brazil bench after being replaced against Serbia
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