Michael Clarke's back and the form of the batsmen are Australia's biggest issues ahead of the first Ashes squad announcement in Sydney on Monday. Clarke's long-standing disc problem flared in his century for New South Wales and he winced in pain during his second-innings 39, which secured a draw for the Blues on Saturday.

Clarke has dismissed the complaint as minor, but his reactions and the speed of his running showed it was serious. It is unlikely he will be risked for New South Wales against Tasmania this week, but at least he knows he is in form.

Apart from Marcus North, Clarke is the only Australia batsman to own a century in the domestic competition this summer. Since returning from India, North has first-class scores of 10, 101, 19 and 1, while Michael Hussey managed just three runs in two Sheffield Shield innings against South Australia. Hussey did produce an ODI half-century against Sri Lanka, but he has registered only 112 runs in his past six Test innings. Both Western Australians have strong supporters in the selection panel.

The opener Shane Watson got starts of 20 and 15 against Victoria while Brad Haddin finished that game strongly with a patient and unbeaten 61. In Hobart Ricky Ponting collected 32 and 5 during a match occurring at the same time as England's batsmen, particularly Alastair Cook and Andrew Strauss, were running into strong form.

While his team-mates struggled to find their touch in the domestic arena, Simon Katich hadn't even made it that far due to a thumb broken in India. Katich turned out for his grade club Randwick-Petersham on Saturday and scored 94, which was a promising sign, but the intensity can't be compared to what he will face at the Gabba on November 25. His next step is to play for the Blues in their Shield game at the SCG on Wednesday.

Australian selectors have been reluctant to include extra batsmen in their home squads unless they are covering for injured men. If Clarke's fitness is already a significant concern Usman Khawaja and Callum Ferguson are the most likely candidates. Khawaja, who toured England with the Test squad during the winter, has the stronger claims due to his 339 first-class runs at 84.75, which put him second on the domestic list behind Andrew McDonald.

The players have another round of Shield matches this week - and an Australia A game against England - but the performances will come too late to influence the selectors for Brisbane. Cricket Australia's marketing commitments mean the team will be named on Monday, 10 days before the opening Test. Andrew Hilditch, the selection chairman, will announce the squad at the Sydney Opera House in a free event, which will give an indication of how much local interest is in the series.

Hilditch spoke last week about wanting only four fast bowlers in the squad, but the excellent return of Ryan Harris in Hobart over the past week may convince him to pick a 13-man outfit. Queensland's Harris, who is back after knee surgery, took a career-best nine wickets for the game and had the bonus of starring in front of Ponting.

Mitchell Johnson remains Hilditch's preferred man as attack leader and Ben Hilfenhaus and Nathan Hauritz are the other bowling certainties. Peter Siddle is fit but not yet firing after a back stress fracture, but he has been a favourite of the panel over the past two years. He has 13 domestic wickets in three matches, including four against the Blues.

Like Katich, Doug Bollinger played in Sydney grade cricket on Saturday, taking 1 for 30 in his first game since hurting his stomach in the Mohali Test. It's not ideal preparation for facing England, but Bollinger is not alone in being under-done.

Likely squad Shane Watson, Simon Katich, Ricky Ponting (capt), Michael Clarke, Michael Hussey, Marcus North, Brad Haddin (wk), Mitchell Johnson, Nathan Hauritz, Doug Bollinger, Ben Hilfenhaus, Peter Siddle, Ryan Harris.

Peter English is the Australasia editor of Cricinfo