Australia have played down suggestions that spinner Nathan Lyon could miss the fourth Ashes Test with an ankle injury.
Cricket Australia confirmed on Wednesday morning that the 31-year-old has picked up an ankle issue, but did not seem to think it would affect his involvement at Old Trafford.
"A bit of a scare for the Aussies at training today, but (Lyon) is all good," CA tweeted.
"He has a slightly twisted right ankle and left training as a precaution. He would have stayed on in a Test."
Star batsman Steve Smith is set to make a return to action on Thursday as Australia begin a three-day tour match against Derbyshire at the County Ground.
Smith was ruled out of the third Test at Headingley after being struck in the neck by a Jofra Archer bouncer during the second test at Lord's.
The former captain passed subsequent concussion tests and was allowed to return to complete his innings, only to be diagnosed with delayed concussion the following morning.
As a result Smith could only sit and watch as England claimed the third Test by one wicket, owing to an incredible innings from Ben Stokes.
The Durham all-rounder scored an unbeaten 135 at Headingley, denying Australia Ashes victory and leaving the series tied at 1-1 heading to Old Trafford.
While Smith returns to prove his fitness ahead of the fourth Test, several key team members will miss the Derbyshire contest to preserve theirs.
Captain Tim Paine sits out the match, with batsmen David Warner and Travis Head and bowlers Pat Cummins, Josh Hazlewood, James Pattinson and Lyon all rested.
Usman Khawaja will take on the role of captain in Paine's absence, while wicketkeeper Alex Carey has been added to the squad for the tour match.
Carey was not named in the initial 17-man Ashes squad and has been playing for Sussex since the World Cup ended last month.
He will take the gloves against Derbyshire but has not been formally added to the Ashes squad and is expected to return to county duty once the match has concluded.
