As England sweats on the fitness of Andrew Flintoff, Australia was dealt another injury concern on Tuesday night with news vice-captain Michael Clarke is battling an abdominal strain.
Clarke, the leading run-scorer in the series, suffered the injury while making an unbeaten 103 to guide Australia to safety in the third Test on Monday.
The injury was only a 'minor strain', a team spokesman said, and he is not considered to be in doubt for the fourth Test starting in Headingley on Friday.
Clarke will not train on Wednesday and will instead seek treatment from the team's medical staff.
"Michael Clarke has an abdominal strain that became sore after the completion of yesterday's game," team physio Alex Kountouris said.
"He will continue to be treated with a view to him being fit for the fourth Test beginning on Friday."
Clarke joins first-choice wicketkeeper Brad Haddin and veteran speedster Brett Lee under injury clouds.
Haddin, who missed the third Test after breaking his left ring finger minutes before the start of the game last Thursday, will have his fitness closely monitored over the next two days.
Graham Manou, the man who replaced Haddin, finished the third Test under duress after being clipped on the fingers while batting during the closing overs of the game.
But Manou will be available to take his place behind the stumps should Haddin remain sidelined.
Lee is making a late bid to prove he has overcome a left side strain which saw him miss the opening three Tests.
Australia captain Ricky Ponting said earlier this week that Lee would have to bowl at full pace in the nets leading into the game to come into contention for selection.
England named Flintoff in its 14-man squad despite concerns over his troublesome left knee.
England selectors gave themselves extra batting depth by including uncapped batsman Jonathan Trott alongside left-arm paceman Ryan Sidebottom and giant quick Steve Harmison.
"We will continue to closely monitor Andrew Flintoff's fitness in the build-up to Headingley," said England selector Geoff Miller.
"His right knee will be reassessed by our medical staff over the next 48 hours and no final decision on his availability will be taken until closer to the start of the Test match."
Australia batsman Marcus North said the tourists did not want to see Flintoff unavailable despite the all-rounder's significant contributions in the second and third Tests.
"We want to play the best side we can play against when we play any other country," North said.
"We have already seen the impact that Andrew Flintoff has had on this series. He had a quiet game with the ball but he had that explosive innings with the bat."
"We want to walk away, taking the Ashes back home, beating a full-strength England side."