Sydney: Jana Rawlinson`s defence of her 400 metres hurdles world title has been cast in doubt after the Australian was diagnosed with a bulging disc in her back, local media reported.
Rawlinson, who recently returned to competition after a toe injury sidelined her for a year, had pulled out of this weekend`s London Grand Prix meeting, a leading news agency said.
"We`ll see what happens in the next few days," her coach Craig Hilliard told reporters.
"If she`s back running pain-free and it does settle down then we`ll look at forging ahead... But if it`s still hanging around then time is starting to impinge."
The Berlin world championships start on Aug. 15.