Ryan Harris is set to miss next week’s Ashes opener, having been ruled out of Australia’s final tune-up due to his troublesome knee.
Harris underwent major knee surgery last year, but struggled to get back to his best in the Test series against India.
The 35-year-old was rested from the second half of the Sheffield Shield season, but did a mountain of work in the gym.
Harris then skipped the West Indies tour due to the birth of his first child and arrived in London feeling refreshed, stronger and fitter.
The veteran paceman returned to the Australian XI last week, taking four wickets in the tour game against Kent.
Harris was slated to face Essex this week in Chelmsford, but pulled up sore after bowling 30 overs in his comeback match.
He still had a sore knee on Wednesday, when play started with Essex skipper Ravi Bopara winning the toss and sending the visitors in, and was replaced by Peter Siddle.
The issue is not serious – Harris rolled his arm over prior to day one in Chelmsford.
But given the right-armer has played so little since January, the setback will almost certainly end his hopes of featuring in Cardiff next Wednesday.
Coach Darren Lehmann, speaking after his charges’ 255-run win over Kent, noted Harris must be “100 per cent before we make him available for selection”.
“Ryan Harris has got to be fully fit,” Lehmann said.
“He’s got to prove to us he can bowl 20 overs in an innings or roughly about, and make sure he’s ready to go.
“If he can do that he certainly comes into consideration.”
Harris suggested last week that he was keen to play all five Ashes Tests, but agreed with Lehmann he was short of a gallop.
“As much as I bowled in Brisbane on centre wickets, it’s very hard to simulate match intensity,” he said.
“My knee’s going to get sore here and there, that will always be the case, but my body itself feels really good.”
If Harris is unable to take the field in Wales, Australia will name an unchanged attack for the first clash with England.
Mitchell Starc and Josh Hazlewood both starred in last month’s 2-0 Test series win over West Indies, while Mitchell Johnson looked back to his best in Canterbury.
