American Jennifer Brady has withdrawn from the Australian Open in January because of a foot injury.
Brady, who is ranked 25th in the world, has not played since retiring from a match against Latvia's Jelena Ostapenko in Cincinnati in August.
The Australian Open takes place from 17-30 January.
Brady will join seven-time winner Serena Williams, world number four Karolina Pliskova and 2019 US Open champion Bianca Andreescu in missing the event.