Australia batsman Michael Clarke will miss at least the second morning of the third Ashes Test against England in Manchester, on Friday with a back problem.
Clarke, who bats at five, was sidelined for almost the entire first day with the same problem. He hurt himself in the second over while fielding before leaving the field.
An Australia team spokesman said Clarke's fitness would be re-assessed at lunch on Friday.
Clarke has suffered from back problems before.
England will resume on Friday on 341 for five. The five-match series stands at 1-1.