The Wallabies lock was forced from the field midway through the first half of the Force's heartbreaking 24-21 loss to the Queensland Reds after he landed awkwardly following a lineout.
And with the start of the World Cup less than three months away, Wallabies coach Robbie Deans will desperately be hoping Sharpe's injury isn't too serious.
The 33-year-old Force captain, who has won 93 Test caps, said it was too early to tell how long he would be ruled out for, if at all.
"At this early stage, I think I've done something to my lateral ligament in my ankle," Sharpe told Fox Sports.
"We'll just have to wait and see how it pulls up tomorrow to see what the extent of the damage is."
Force coach Richard Graham said Sharpe's injury would be assessed on Sunday.
"At this stage, I haven't looked at him. We've got medicals at 10 o'clock in the morning so we'll check it out then," he said.
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