Australia captain Michael Clarke has been ruled out of the ICC Champions Trophy group match against England with a lower back injury.
Clarke was absent from the warm-up games against West Indies and India and his continued fitness concerns will be a worry ahead of the start of the Ashes series.
Cricket Australia physiotherapist Alex Kountouris said: "Michael is making steady progress in his recovery from the recent lower back injury but is yet to return to training.
"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."
Clarke has suffered back problems occasionally during his career and his priority will be a return to fitness ahead of the Ashes series which starts at Trent Bridge on July 10.
He most recently suffered a recurrence with the problems during the 4-0 series defeat in India and missed the final Test due to back and hamstring problems.
Clarke, 32, is one of Australia's main batting threats and he has undergone specialist treatment in London in a bid to regain his fitness ahead of the Champions League fixtures.
However, he has now lost his race to be fit for the opening match, and due to the compact nature of the Champions Trophy - with Australia's three pool games wrapped up by Monday week - he is short on time to return to full fitness to feature in the tournament with questions now hanging over his Ashes involvement.