Cristiano Ronaldo could miss Portugal's final World Cup group stage game against South Korea on Friday.

· Ronaldo missed training on Wednesday

· Santos unsure if he will play against Korea

· Portugal already through to last 16

WHAT HAPPENED? Portugal coach Fernando Santos confirmed that the attacker's availability for the Group H match is in doubt after he missed training on Wednesday. The specific nature of his injury has not been confirmed, but he's reportedly dealt with knee pain.

WHAT THEY SAID: "I think it is 50-50 if he plays or not, we'll see," Santos said at a press conference. "It will depend on if and how he practices today, if we see he is in good condition. There is a plan for if he is not available."

THE BIGGER PICTURE: Portugal are already through to the knockout rounds of the World Cup after winning their first two matches against Ghana and Uruguay.

WHAT NEXT FOR PORTUGAL? Santos' team will hope to make it three straight wins in the World Cup when they take on South Korea to ensure they finish as Group H winners.