Australian fast bowler Ryan Harris is emerging as a slight doubt for the third Ashes Test with England because of a knee injury.
Harris, 34, played in the first two Tests in Brisbane and Adelaide as Australia opened up a 2-0 lead in the series.
He has played second fiddle to Australia's chief destroyer Mitchell Johnson but his absence in Perth - where the wicket is ideally suited to fast bowling - would be a blow to the hosts.
The Queensland veteran, who has taken eight wickets at 20.23 so far in the series, is expected to train on Thursday but his problematic knee is reportedly sore.
A Cricket Australia spokesman said: "Ryan Harris has had an ongoing knee issue throughout his career which we manage after each Test he plays."
James Faulkner, who was 12th man in Brisbane and Adelaide, was a contender to come into the side but he has been ruled out with a fractured thumb.
That means Doug Bollinger and Nathan Coulter-Nile, who were on standby, will step up to replace Harris or come into the side should Australia opt to play four seamers.
Skipper Michael Clarke is hopeful, though, that Harris will be fit to play in the third Test.
Clarke said: "I hope everyone will come up. There is the obvious one, in 'Rhino' bowled today, so we are going to wait and see how he pulls up.
"But I am confident he will be fine."
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