By Martin Gough BBC Sport Online

England's selectors are expected to name a 17-man squad on Tuesday for the Ashes tour of Australia.

But before then they will have to answer some tough questions regarding the availability of leading batsman Graham Thorpe.

And the fitness of several bowlers, chief among them Darren Gough, remains a worry.

Have your say: who should England pick?

BBC Sport Online runs the rule over the players with the best chance of making the plane Down Under.

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OPENERS
Certainties: Michael Vaughan, Marcus Trescothick
Others: Robert Key

In worse summers, Key could have done enough in two Tests against India to secure himself a spot.

But the form of Vaughan and Trescothick has been sublime when they have batted together, Trescothick proving at The Oval that he has fully recovered from a fractured thumb.

Mark Butcher has enough experience to fill in as opener should an injury replacement be required.

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MIDDLE ORDER BATSMEN
Certainties: Nasser Hussain, Mark Butcher
Others: John Crawley, Graham Thorpe, Mark Ramprakash

Thorpe's readiness could be vital

There is no doubt that if Thorpe's mind is fully on the game he is one of England's greatest assets.

But the selectors will be keen to make sure that there is no repeat of his early exit from the tour of India.

Ramprakash averages 42.40 against Australia, compared to Crawley's 26.31 but the Surrey man has been ignored all summer - the best indicator in this era of joined-up selection thinking.

ALL-ROUNDERS
Certainties: Andrew Flintoff
Others: Craig White, Dominic Cork

England have never been confident of fielding just four bowlers, and the role of all-rounder has grown in significance of late despite a worrying lack of form and fitness among the leading candidates.

Flintoff is expected to recover from hernia surgery in plenty of time but, should White fail to prove his fitness after a side strain, Cork looks set for a spot.

This is despite the Derbyshire captain gaining a growing reputation as a swing bowler who rarely swings the ball, a fact his half-century at The Oval can barely make up for.

WICKET-KEEPERS
Certainties: Alec Stewart
Others: James Foster

Foster looks set for a learning role

On his way back from a broken thumb, the centrally-contracted Foster looks likely to take his place behind the stumps for England's four tour matches as part of a learning process.

Stewart may have been thought past his best a few months ago, but he has more than justified his return, is a sure pair of hands and a sixth batsman.

SPIN BOWLERS
Certainties: Ashley Giles
Others: Richard Dawson

Adelaide and Sydney are both expected to turn enough to justify the inclusion of two spinners in an XI but, Giles aside, England simply do not have spinners classy enough to exploit it.

The England team have made much of their belief that pace will win the series, and that should be enough to gain an extra spot for a fast bowler at the expense of Dawson, who is on hand with England's Academy.

FAST BOWLERS
Certainties: Andrew Caddick, Matthew Hoggard
Others: Darren Gough, Alex Tudor, Simon Jones, Steve Harmison

The picking of a 17-man squad would appear to indicate that a half-fit Darren Gough will make the trip, with the hope that he will fully recover from his knee injury at some point.

It will also make space for Jones and Harmison, both of whom have made Test debuts this summer, both to pack their bags for the trip.

Should England opt for an extra batsman or spinner, Hamison is the most likely to miss out, as long as Jones has recovered from a side strain.

Possible England Ashes squad: Nasser Hussain (capt), Michael Vaughan, Marcus Trescothick, Mark Butcher, John Crawley, Graham Thorpe, Andrew Flintoff, Craig White, Alec Stewart, James Foster, Ashley Giles, Andrew Caddick, Matthew Hoggard, Darren Gough, Alex Tudor, Simon Jones, Steve Harmison.