Australia have named their squad for next week's first Ashes Test, but their starting line-up is no clearer. Xavier Doherty and Callum Ferguson were the major surprises in a bloated 17-man group that also included Usman Khawaja, Ryan Harris and Peter Siddle, but there was no place for the backup opener Phillip Hughes, who was the only unexpected omission.

The squad, which is bigger than England's touring party for the entire series, will be trimmed to 12 or 13 after this week's round of Sheffield Shield matches before the first Test begins at the Gabba next Thursday. The selectors are also keen to see how some of the contenders perform for Australia A in their match against England starting on Wednesday in Hobart.

The four-day game between New South Wales and Tasmania shapes as a particularly fascinating contest, with the spinners Hauritz and Doherty to go head to head on an SCG pitch that should offer assistance. The inclusion of the left-armer Doherty, who made a promising ODI debut this month but was viewed as a limited-overs specialist, has placed extra pressure on the incumbent Hauritz, who has struggled over the past month.

"Nathan Hauritz has performed exceptionally well over the past 12 months for Australia," the chairman of selectors, Andrew Hilditch, said. "One of the biggest decisions we will need to make is whether we go into the first Test in Brisbane with a right-arm offspinner or with the variation of a left-arm orthodox bowler.

"Xavier Doherty has been very impressive in both limited-overs and first-class cricket, in particular last season and the start of this season, and it will be a great opportunity for us to observe both of the spinning options in the Sheffield Shield clash between New South Wales and Tasmania at the SCG this week."

Hilditch's comments suggest the selectors are not considering an all-pace attack at the Gabba, where the seam-friendly conditions sometimes encourage sides to risk leaving out their frontline spinner. That means the most likely pace attack is Mitchell Johnson, Ben Hilfenhaus and Doug Bollinger, who made a promising return in club cricket on the weekend.

Bollinger has been out with an abdominal strain since the first Test in India last month, and he collected 1 for 30 in ten overs for Fairfield on Saturday. He will continue his return in the Sheffield Shield game and providing he comes through unscathed, will be a certain starter on a Brisbane surface that should offer him some assistance.

His recovery also reduces the chance of Siddle being included for his first Test since January, while the in-form Harris would need to also shake off a knee problem if he was to make the side. Harris bowled himself into contention with a match haul of 9 for 140 for Queensland at Bellerive last week but after the match had a swollen knee - he had surgery on the joint during the off-season - and his availability won't be known for several days.

"Ryan Harris has a chronic knee injury that requires ongoing management," the team physio Alex Kountouris said. "As such he will not play in the next round of Sheffield Shield games or for Australia A starting 17 November to allow his knee to fully recover. His availability for the first Ashes Test will determined later this week."

There are unlikely to be any surprises in Australia's batting line-up, although they are waiting to confirm the fitness of Michael Clarke, who suffered a recurrence of the disc problem in his back while playing for New South Wales on the weekend. Clarke will sit out of this week's Sheffield Shield match but he is hopeful he will take his place at the Gabba.

"I'm not going to play against Tasmania on Wednesday," Clarke said. "I'm going to give myself another few days off to get my back right. But I'm confident that if I do all the right things over the next week I'll be 100% ready to go come Brisbane."

Unless Clarke succumbs to the problem, there shouldn't be any changes to Australia's established top six, meaning Khawaja and Ferguson will have to wait to receive their baggy greens. Their selection is a strong indication that they will be vying for a position in the middle order should the selectors lose faith with Michael Hussey or Marcus North during the summer.

The exclusion of the opener Hughes is a sign that Simon Katich will be fit for the Test, having been out of action due to a broken thumb. Katich made his comeback in grade cricket on the weekend, making 94 for Randwick-Petersham, and will line up for New South Wales in their four-day match this week.

Australia squad Simon Katich, Shane Watson, Ricky Ponting (capt), Michael Clarke, Michael Hussey, Marcus North, Usman Khawaja, Callum Ferguson, Brad Haddin (wk), Steven Smith, Mitchell Johnson, Nathan Hauritz, Xavier Doherty, Ryan Harris, Peter Siddle, Ben Hilfenhaus, Doug Bollinger.