Australian hurdler Sally Pearson is expected to announce that she is to withdraw from the Commonwealth Games on the Gold Coast due to an Achilles injury.
The 31-year-old was the favourite to retain the 100m hurdles title she first won in 2010 in Delhi, then successfully retained in Glasgow four years later, and was also due to compete in the sprint relay.
Pearson - also Olympic champion in 2012 - appeared at the Games' opening ceremony last night as the final runner of the Queen's baton relay, having been overlooked to serve as the nation's flagbearer.
Earlier this year Pearson suffered an Achilles injury which kept her on the sidelines for several weeks, but the athlete recently insisted that she was confident of being fit enough to compete.
This morning Team Australia called for a media conference at 1pm local time (4am UK) for a 'Sally Pearson Announcement' involving Pearson and Australia's team doctor.
The athletics programme at the Games is due to get underway on Sunday.