Belarussian Azarenka , who would have been seeded six at the championships, has not played since retiring from a first-round match at the French Open last month.
It is yet another blow for the two-times Australian Open champion who has been plagued by foot injuries.
Her withdrawal means five-times champion Venus Williams will move up into the top eight seeds.
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(Reporting by Martyn Herman; Editing by Toby Davis)
