South Korea v Poland | Group D | Busan
Tue 4 June | 1230 BST | Live on BBC 2
South Korea midfielder Lee Young-Pyo is doubtful for his country's opening match
He was kicked on the calf during practice on Saturday and later sent to hospital to determine the extent of the injury.
Coach Guus Hiddink said: "If Lee Young-Pyo is not fit, of course then there's a change in the line-up. But I will not re-compose the whole team.
"There is no first eleven yet. If one player gets injured, there is another player who can quickly replace him."
South Korea have yet to win a World Cup finals match, but Hiddink will not adopt a cautious attitude for their opening game on Tuesday.
He said: "We must not sit back and wait, we must try to take control and the initiative.
"That won't be not easy though. Poland are a powerhouse in Europe."