The conclusion seems inescapable: if Headingley Carnegie produces a result - highly likely given that since 1981 there have been only two draws there - then to the winners will go the Ashes.

This is self-evident in England's case, as a win would give them an unassailable lead in the series and spark off the kind of jingoism that would make Edgbaston's booing of Ricky Ponting look tame indeed. But if Australia turn things around in Leeds, it is difficult to see how Andrew Strauss's team will bounce back and bowl Australia out twice on traditionally the flattest pitch of them all, the Brit Oval. The next five days, then, shape as the most pivotal of the summer.

So what a time for Andrew Flintoff's knee finally to bow to the inevitable. He bowled in the nets for 40 minutes yesterday without looking anywhere near full fitness, and the heaviest of knee braces and glummest of moods would have done little to reassure his supporters.

Last night, as England pondered their options, it was looking increasingly unlikely that he would play.

Strauss said yesterday that the selectors would make a hard-nosed, unemotional decision and they, not Flintoff, would make the call, although clearly they will take notice of his mood and wishes.

Headingley was always going to be the biggest hurdle for him, coming so hard on the heels of Edgbaston, and it would be an amazing turnaround from his final-day lassitude there if he is fit to take the new ball today. And, even if he can bowl a decent first spell, can he guarantee a second and a third? And what about the next four days? It would be a gamble too far.

Contrary to popular opinion, Flintoff did not have cortisone injections before the last Test. Rather, he had lubricant injections, which are nothing like as dangerous. He could endure more of them but each day of action brings greater swelling, nature's way of demanding some rest. One last hurrah at the Oval beckons.

In Flintoff's likely absence, England have some awkward decisions to make. Do they stiffen their batting, bringing in Jonathan Trott - who incidentally was parading around yesterday in a shirt with both his initials and England number on - so changing the policy of the summer at a stroke?

This would send out defensive signals, a battening-down-of-the-hatches, protecting-the-lead kind of a decision, which would go against Strauss's well-aired pronouncements about how attacking cricket is the best way of beating Australia.

If Trott plays, does that mean Stuart Broad is vulnerable in a four-man attack? Broad has struggled to be an effective fourth seamer this summer, never mind third, and if he does miss out, who should be England's third pace bowler, Stephen Harmison or Ryan Sidebottom?

Better, with all this uncertainty, to make just one change, a straight swap of Harmison for Flintoff. It would be the positive thing to do; it would necessitate less upheaval and allow for a like-for-like replacement with the ball. In any event, debutants in Ashes series have rarely fared that well in recent times, and Broad would be as likely to make his mark with the bat as Trott.

If Strauss was faced with the trickiest decisions on the eve of Test, Ponting has his own problem to deal with, namely Brett Lee. The fast bowler has been bullish about his fitness in the build-up to this game but, as with Flintoff, time has not been on his side, and there have been previous occasions when Lee has failed to deliver.

It would be a huge risk, in a four-man attack, to play him without any cricket under his belt, and he, too, may have to wait until the Brit Oval, when the benefits of an outing against England Lions next weekend should have proved beneficial.

With bare concrete substructures protruding at the Kirkstall Lane End, Headingley Carnegie is a ground turning its attentions at last to the future and away from the past. Ponting could have been forgiven for hoping for a better tomorrow, too, because his immediate future as Australian captain could depend on what happens over the next five days. To lose the Ashes once in England is just about acceptable, to lose them twice, well, that could be seen as unnecessarily careless.

Such knowledge is likely to sharpen his game and his punting instincts. Ponting has an outstanding record as a batsman at Headingley, scoring hundreds in both his appearances there. He could do with some runs now, the well having run dry since Cardiff. Is the pressure of leading a modest team taking its toll? He has looked fidgety, for sure, since his opening salvo of this series, but he is often a poor starter and champions tend to raise their game when it matters.

What is certain is that his reaction to the moment will be a positive one and Australia's team selection is likely to reflect the captain's mood, even if he has no formal vote on selection.

Nathan Hauritz has performed better than his reputation suggested he would, but he is likely to be less effective at this venue than anywhere else and it takes a leap of faith to imagine him as a match-winner.

Expect Australia to play four seamers, with Marcus North accepting the spin-bowling duties and Stuart Clark finally getting the chance to show how badly Australia have missed his control.