Captain Robin van Persie may miss the Netherland's World Cup semi-final against Argentina as he is struggling with an upset stomach.
Van Persie has been instrumental in the Netherland's run to the last four of the tournament, but he had to train separately from his team-mates on Tuesday after complaining of a stomach problem.
Coach Louis van Gaal confirmed on the eve of the game in Sao Paulo that his star striker, who has scored three goals in Brazil, is a serious doubt for the last-four clash.
"He has a stomach problem, an intestinal problem. I don't know (if he will play)," Van Gaal told a press conference.
"I will decide (on Wednesday).
"Van Persie is our captain so he is very important to us.
"In principle my captain always plays, but he has to be fit."
There was some good news for Van Gaal on Tuesday as injury doubts Ron Vlaar and Leroy Fer took part in training.
In an interesting development, midfielder Nigel de Jong was also involved even though he had been expected to miss the rest of the World Cup after suffering a groin injury in the group stage win over Mexico.
"If his reaction is good and he can play, then the miracle can come true," Van Gaal said.
"If his reaction is good and he can play, then the miracle can come true," Van Gaal on Nigel de Jong's return to training
But even if De Jong makes a shock return to the XI for the Argentina match, it will mean nothing if Van Persie is ruled out.
Holland have relied heavily on the Manchester United striker, and fellow star Arjen Robben, in Brazil.
Both players scored in the penalty shoot out win over Costa Rica which sent the Dutch through to their second successive World Cup semi-final.
That match was a draining affair as Holland battered the Costa Rica goal, but they could not beat Keylor Navas inside 120 minutes.
Van Gaal thinks his players will have recovered their fitness by the time they face Alejandro Sabella's team.
"In general I give the players two days to recover, so if you have one day less it's an issue, a problem," Van Gaal said. "But a top athlete can perform so my players will be in shape."