Olympic silver-medallist Leon Taylor has pulled out of the British Diving Championships with a hernia.
Taylor has suffered a string of injuries since winning silver in 2004
The 30-year-old, runner-up at the 2004 Olympics in the 10m synchronised with Peter Waterfield, will undergo surgery on 15 January.
It means Tom Daley, 13, and Blake Aldridge will compete at February's World Cup where they will try to win Britain a spot at the Beijing Olympics.
They are also in action at the national championships, which begin on Friday.
Taylor, who has had four bouts of shoulder surgery since 2004, plans to attend the event to support Aldridge and Daley - to whom he is a mentor.
"It's great we've got such healthy competition domestically," Taylor, who plans to retire after the Beijing Games, told BBC Sport.
"If we didn't have a back-up pair - and obviously Tom and Blake are much, much more than that - we might not be able to get a place at the Olympics, but they are more than capable of doing that."
The World Cup takes place in Beijing and will also act as an Olympic test event.
The top eight finishers will qualify their countries for the Games later this year.
If Daley and Blake earn Britain a qualifying place in Beijing, they will then go head-to-head with Taylor and Waterfield in June to decide who competes at the Olympics.