Melbourne: Injured batsman Kevin Pietersen admitted England had only an 'outside chance' of winning this year's World Cup after their dismal start to the triangular one-day series here.

Pietersen faces up to five weeks on the sidelines after a Glenn McGrath delivery broke one of his ribs during Australia's rampant eight-wicket win here.
 

"If we gain some experience and pick up some tips about how a formidable Australian side plays, and improve our game by 10 or 15 per cent," Pietersen said.

"The World Cup is a knockout tournament and, who knows, we could have an outside chance of doing well in the competition," he said.
 

Pietersen said he would 'champing at the bit' to be ready for the World Cup, which starts in the Caribbean on March 13.
 

"I'll just have to bide my time but I'm a pretty quick healer, so I'll get myself as fit as I can as quick as I can and I'll be champing at the bit to get out to the Caribbean," he said.
 

Pietersen's injury was yet another setback for embattled England as they lurch towards the World Cup and will significantly affect their chances in the series here, also involving New Zealand.

Speaking after Friday's match, Australian captain Ricky Ponting noted that England's one-day tactics revolved around the powerful right-hander.
 

"Pietersen has been their best batsman throughout the summer," he said.

"A lot of their one-day cricket tactics are based around him and they will miss him a lot," he said.
 

Despite England winning just seven of their last 28 limited-overs internationals, Pietersen averages 56.50 and is second in the ICC rankings behind Australian Mike Hussey.
England called up promising middle order batsman Ravi Bopara as Pietersen's replacement in the squad.

The right-hander, 21, was part of the England Cricket Board Academy squad that played in Perth during the Ashes Test series and got the nod ahead of Owais Shah, Alastair Cook, Robert Key and Vikram Solanki.

"Ravi has been brought in because he is a middle order batsman who impressed in his time with the Academy in Perth earlier in the winter," said chairman of selectors David Graveney.

Graveney said England weren't keen to shuffle their top order, despite Friday's demoralising loss.

Although Ed Joyce is expected to take Pietersen's place when England play New Zealand in Hobart on Tuesday, Bopara is likely to make his international debut before the series is over.
 

"We are happy with the top order of (Andrew) Strauss, (Michael) Vaughan and (Ian) Bell," Graveney said.

"We also see the injury to Kevin Pietersen, while unfortunate, as offering a great chance for Ed Joyce to stake his claim for a place in the ICC World Cup," he said.