IRENE, South Africa (Reuters) -- Italy goalkeeper Gianluigi Buffon missed training for a second day on Wednesday after going to hospital for tests on a sciatic nerve problem amid speculation he could be ruled out of the World Cup.

The 32-year-old, who has endured an injury-hit two years, suffered the problem before Monday's 1-1 Group F draw with Paraguay and was substituted at halftime.

Buffon said afterwards he hoped to return to training in two days but that has not been possible and follows a statement from the world champions on Tuesday which said it was impossible to estimate when he might return.

A team spokesman said Italy may issue another statement later on Wednesday depending on the results of tests in Pretoria.

Inexperienced Cagliari keeper Federico Marchetti, who replaced Buffon on Monday, is therefore gearing up to start Sunday's second group game against New Zealand in Nelspruit.

Italian media have speculated 2006 hero Buffon will also miss the final group game against Slovakia on June 24 and may struggle to make any of the rest of the competition but Italy will only say his condition is being monitored daily.

Midfielder Andrea Pirlo, who missed the opener with a calf problem and is set to skip the New Zealand game as well, went to hospital with Buffon for his own check-up.

The rest of the squad trained normally in warmer conditions from Tuesday's biting cold.

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