Graeme Swann backing Andrew Flintoff to play through the pain

England's leading off-spinner admitted to being concerned as Flintoff struggled through his 17 overs and seemed to be troubled throughout with a recurrence of his recent knee problems.

It has led to speculation that all-rounder Flintoff, who has announced his intention to retire from Test cricket at the end of the Ashes series, will not be able to bowl to his maximum through today's final day, when Australia resume on 313 for five chasing a world-record victory target of 522.

But Swann, a long-term friend of Flintoff, has calmed fears about the involvement of both the all-rounder and Kevin Pietersen, who also seemed to be struggling with a back injury, while Graham Onions is expected to be able to bowl despite an elbow problem.

"You don't have to worry about injury with Fred," said Swann. "Every time he goes off the field and comes back on, you think 'is that going to be the end of him?' and he bowls at 95 miles per hour again. KP had a stiff back but he came back out because he is desperate to be out there with all the boys. As far as we are concerned there are no problems there with injury."

Regardless of the outcome of the Lord's test, however, England captain Andrew Strauss and the team of selectors must spend the next eight days making contingency plans for the potential absences of Pietersen and Flintoff for future matches.

Should Pietersen's Achilles problem, which relates to his back injury, deteriorate to the extent that he would be forced to sit out the Third Test, batsman Ian Bell - in the 13-man squad for this game - would be the most likely replacement.

Pietersen has already had four injections in an attempt to see him through the series, and he is set to be examined further after this Test, with the third match at Edgbaston beginning next Thursday.

If Flintoff's problematic knee fails to hold up, fast bowler Steve Harmison would be the favourite to replace him - but this would leave the batting line-up looking fragile, with Stuart Broad forced to come in at No7.

Flintoff left the field after his opening seven-over burst yesterday, and winced more than once during his follow-through as he bowled in the afternoon.