LONDON: Australia captain Michael Clarke has been ruled out of his side's opening Champions Trophy match with England on Saturday due to a back problem, Cricket Australia announced on Friday.

Clarke, 32, has already missed Australia's warm-up games with the West Indies and India, raising concerns about his participation in the Ashes series later this year.

“Michael is making steady progress in his recovery from the recent lower back injury but is yet to return to training,” said Cricket Australia physiotherapist Alex Kountouris.

“He will remain in London over the coming days to continue his rehabilitation and will not be available for the first match against England on Saturday.

“How he responds to the ongoing treatment will determine his availability for the match against New Zealand next Wednesday.”

The first Ashes Test is scheduled to start at Trent Bridge on July 10.