Michael Clarke faces Ashes fitness race

Injured Australian batsman Michael Clarke is unlikely to face England in this week's first Ashes test unless he bats in training on Tuesday, captain Ricky Ponting said today.

Vice-captain Clarke suffered a recurrence of a long-term lower back problem in a recent Sheffield Shield match and failed to suit up for nets on Monday in Brisbane, where the first test begins on Thursday.

"He's been in this situation a few times in the last couple of years, he's had these niggly things with his back and been able to come up most times," Ponting told reporters in Brisbane.

"If we don't see him bat tomorrow then I think it will be hard to see him considered for the game.

"It will depend on how much he is able to do tomorrow and Wednesday but someone as important to our team as he is we'd probably wait until Thursday morning."

Uncapped batsman Usman Khawaja was brought into the squad on Monday as cover for Clarke, who has hit 4,549 runs in 64 tests since making his debut in 2004.

"Didn't train today, back a little stiff," Clarke posted on his Twitter page. "Confident if I keep listening to our physio and doing the right things I will be fit for thurs."

Free-scoring Khawaja was in the original 17-strong squad for the test but dropped when it was reduced to 13 on Saturday after he failed to impress for Australia A against England in Hobart.

"As there is some doubt over Michael Clarke's fitness for the Brisbane test match, it was felt prudent to bring a standby player into the squad," chairman of selectors Andrew Hilditch said in a news release.

"We intend to give Michael as much time as possible to prove his fitness and a decision on his availability will be made in consultation with the team's medical staff after the next two days of training."

Team physiotherapist Alex Kountouris said Clarke was making good progress and was expected to train on Tuesday and Wednesday.

There was more bad news for Australia, however, when Tim Paine, the back-up to wicketkeeper Brad Haddin, was discovered to have broken a finger in a Twenty20 match in Brisbane on Sunday.