Clarke clears first fitness obstacle

Michael Clarke has conquered his first major obstacle to proving his fitness for the opening Ashes Test while Peter Siddle has firmed as Australia's third bowler for the Gabba. Clarke batted in the nets for almost an hour on Tuesday and played a full range of shots without any noticeable discomfort from his degenerative back problem.

Clarke, the vice-captain, has been the major worry this week after picking up the problem earlier in the month, but Alex Kountouris, the team physio, said he was "really positive" after the training session. "He got through today well and it's important to wait to see how he pulls up tomorrow," he said. "Michael will bat again on Wednesday and a final decision will be made on Thursday morning."

The sight of Clarke pulling, driving and dancing down the wicket during his session of throw-downs provided a much-needed boost for the locals, who have experienced a difficult time over the past month. "That's good signs for him and for Australia," Mitchell Johnson said. "He's still got two another days to prove himself. To have someone like Michael not in the team would be a big loss for us."

Usman Khawaja remains on standby but Australia's squad is taking shape, with Steven Smith, the legspinning allrounder, released to play for New South Wales. Siddle has not appeared in a Test since January but has moved ahead of Doug Bollinger for the final bowling spot.

Johnson and Ben Hilfenhaus are the two certainties in the attack while Siddle is capable of providing some right-arm menace after a long and detailed recovery. "Out of us four, it's going to be a tough time for one of us and there will be highs," Siddle said. "Whoever gets that opportunity will be ready to go."

Bollinger's action has usually been a selling point but in this team there are also the left-armers Johnson and Xavier Doherty, the finger spinner in line for a debut. Bollinger has played only one Sheffield Shield match since hurting his stomach in India, limiting his chances to impress.

The Gabba pitch is green and the square is soft, prompting suggestions Australia should lean towards a four-man pace attack. That combination is extremely unlikely given the allrounder Shane Watson's ability to deliver around 15 overs a day of medium-fast.

When asked if the four specialist quicks would corner Ricky Ponting to push for an all-pace attack Siddle said: "That's what we'd always like to say, and Marcus North has taken a Test five-for. We will always put that out there. It's up to selectors which way they go. It always makes it harder when you've got Watson there."

Siddle has been in demand this week and was a guest at a Test match lunch where he spoke of his desire to charge in and "have a crack" at England. He was a key member of the team during the 2009 loss, taking 20 wickets at 30.80, and has done some serious remodelling of his body during his time out with a back stress-fracture.

"I'm a new and improved person and a new and improved bowler," Siddle said. "There's a lot more to do for Australia cricket."