Great Britain's 470-class Olympic Games sailor Elliot Willis has been diagnosed with bowel cancer.
The 32-year-old and team-mate Luke Patience are the world number two-ranked pair and were selected for next year's Olympics in Rio de Janeiro.
A decision is yet to be made on the two-time world champion's campaign in Brazil, with Willis waiting on a full medical assessment.
"Clearly it's pretty shocking news to receive, as I'm sure anyone who's been affected by a similar thing would understand," he said in a statement.
"It's still my dream to win Olympic gold but right now my focus and energy needs to be on getting better.
"My health is my number one concern and I will take advice and recommendations of the medical professionals as they establish the right course of treatment for me."
Patience offered his support to his team-mate and said nothing will take priority over Willis' health.
"I'm gutted for Elliot. Everything else takes a back seat when something like this happens. Elliot absolutely needs to do what's best for him and I'll support him in whatever way I can," Patience said.
"Inevitably he will need to take some time out of the boat so we will discuss the best approach to keeping the campaign moving forward and take some decisions on that front when we know more."