Tony Ally has withdrawn from Britain's team for the World Diving Championships after rupturing the cruciate ligament in his left knee.
Ally faces a tough battle to regain his fitness
The City of Sheffield diver suffered the injury while giving a demonstration to a group of young divers.
Ally, 33, may need surgery and could be out of action for six months.
"I'm gutted to miss out on Melbourne but I'm committed to making sure I'm back for the end of the season to give myself a shot at Beijing," said Ally.
His withdrawal means a call-up for 19-year-old Ben Swain from City of Sheffield, and he will partner Nick Robinson-Baker in the 3m synchro event.
Olympic and world medallists Leon Taylor and Peter Waterfield will lead Britain's squad.
The duo returned to winning ways at last month's British Championships after Taylor proved his fitness following a fourth shoulder operation.
They won bronze in the 10m synchro at the 2005 World Championships and silver at the 2004 Olympics in Athens.
The 11-strong team will aim to seal their places for the 2008 Olympics.
The squad comprises Tonia Couch (Plymouth); Tandi Gerrard (City of Leeds); Stacie Powell, Blake Aldridge, Gareth Jones, Pete Waterfield (all Southampton; Jodie McGroarty, Hayley Sage, Nicholas Robinson-Baker, Ben Swain, Leon Taylor (all City of Sheffield).
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