"My knees are giving a lot of trouble and I am again flying to London on Sunday for another check up. That makes my chances for the World Cup fifty-fifty at the moment,” Shoaib told reporters at the Gaddafi Stadium where the Pakistan training camp for the World Cup commenced on Friday. Both Shoaib and Mohammad Asif attended the two sessions of the camp on the first day.

A big question mark still hangs over the participation of both fast bowlers in the World Cup since they are yet to give their urine samples to PCB authorities.

The Pakistan team is set to leave for the West Indies on March 1 and it appears highly unlikely that the PCB would get the samples of the Shoaib and Asif prior to that deadline.

It has been learnt that Asif will also be flying to London alongwith Shoaib this week and sources close to PCB say that both will be having a ‘secret’ dope test conducted in England to check the quantity of banned substance nandrolone in their bodies.

According to the sources, the fast bowlers will only give the urine samples to PCB if they get a clean bill in England, otherwise they are likely to opt out of the mega event citing injuries to knee and elbow respectively.

Rumours also abound that both have already gone through a ‘secret’ dope test in London and have found that there is still a substantial quantity of nandrolone in their bodies which may land them into trouble with the ICC.

Shoaib, who returned from South Africa following a hamstring injury during the second Test at Port Elizabeth, was also fined USD 2500 for misbehaving with Pakistan coach Bob Woolmer on the tour. The maverick pacer, however, denied any rift with the coach on Friday.