By Timothy Collings
RUSTENBURG, South Africa (Reuters) - England captain Rio Ferdinand's participation in the World Cup was hanging in the balance on Friday after he hobbled out of hospital on crutches following a scan on his injured left knee.
The 31-year-old defender suffered the injury in the final minutes of England's first major training session in South Africa after he went into a tackle and fell badly.
British media reported Ferdinand had been ruled out of the tournament which begins next Friday but there was no official confirmation from the England camp.
Earlier in the day, manager Fabio Capello said he hoped the injury would not be serious, but added that he had put reserve uncapped defender Michael Dawson on stand-by to fly to South Africa if Ferdinand was ruled out.
"More bad news -- Rio suffered a knee problem and he has just gone to hospital for a scan. We hope it is not a bad injury," Capello told reporters.
The Italian also confirmed that goalkeeper David James had missed training due to a nagging knee injury aggravated by the long overnight flight from London.
However, there seemed to be promising outlook for midfielder Gareth Barry, who was recovering from an injured right ankle.
"He is getting better and better every day. He started training with the team. He will go to the gym this afternoon with the physiotherapist and always train with the team in the mornings," said Capello before adding that he was unsure if Barry would feature in England's opening match against the U.S. on June 12.
"He will not do everything just yet and we have to be a little careful with him just at this moment."
The England manager added that he was thrilled to be in South Africa and was revelling in finally having a serious game to prepare for. "It is seven months now since our last qualifying game," he added.
Ferdinand took over as England captain after fellow defender John Terry was stripped of the job in February because of an off-pitch scandal involving his private life but he has not played regularly for Manchester United this season due to a succession of injuries.
He played for England in the 2002 and 2006 World Cup finals tournaments and has made a total of 78 appearances, scoring three goals.
(Editing by Jon Bramley and Pritha Sarkar)