Australia forward Harry Kewell missed Monday's World Cup second round defeat by Italy as he was suffering from gout.
Kewell was forced to sit out Australia's 1-0 defeat by Italy
The Liverpool man, 27, was diagnosed with the disease on Saturday, but the news was kept secret in the hope that he would recover in time to play.
"He's got gout on his foot," team-mate Scott Chipperfield revealed.
"He's in a lot of pain, he can't walk, he's walking on crutches. It was disappointing for us, because we could have done with him."
Gout is a painful form of arthritis which is caused when crystals of uric acid build up in joints, most commonly the big toe.
Socceroos captain Mark Viduka added that Kewell had been given as long as possible to recover in time to play.
"People say it's a 24-hour, 48-hour thing and we were hoping it would be all right," said the striker.
"(Assistant coach) Graham Arnold had that when we were in (the training) camp and he was all right in 24 hours, but Harry woke up this morning and was still struggling."