Dutch wing wizard Arjen Robben is a major doubt for the finals, after getting injured during the 6-1 rout of Hungary.
Robben came on in the second half as a substitute and scored two goals, but went off injured in the 85th minute with a hamstring injury.
Coach Bert van Marwijk told reporters that Robben will undergo a scan on Sunday to determine the extent of the injury.
"He felt a sharp pain," said van Marwijk. "That does not bode well, but I do not lose hope," he said.
Robben has been in sizzling form for the Bayern Munich this season, leading them to Cup and league double as well as the Champions League final.
His absence would be a major blow to the Dutch. The Dutch squad will leave for South Africa today without Robben, and coach Van Marwijk fears the 26-year-old may not even follow his teammates to the finals.
"My first thought was this can't be true, the end the final warm-up match, everyone is fit and then this," he added.
"We now have to wait. I can replace Robben until 24 hours before our opening match but as long as there is hope he recovers in time he will stay in the squad."
Netherlands will open its World Cup campaign on June, 14 against Denmark.