The Swiss rowing association has threatened to ban Xeno Müller from next month's world championships in Lucerne unless the Olympic gold medallist apologises over statements he made in an American magazine interview.
"The association will only select Müller provisionally for the world championships," said director René Fischer, adding that the Swiss star had 14 days to send a written apology.
In his interview with the Independent Rowing News, the California-based athlete launched a blistering attack on association officials, who he described as "a bunch of arseholes in suits."
He also singled out president Walter Kägi for similar criticism, but later told Swiss journalists that he had meant to refer to Hansjörg Wirz, the head coach of Swiss Olympic.
Asked what it was like being a Swiss living in the United States, Müller told the rowing magazine that the Swiss association had destroyed his motivation by paying him less prize money after his silver medal in Sydney than he had been paid for his gold in Atlanta.
Because of this he said he was happy not to live in Switzerland.
Müller's two Olympic medals in the single sculls discipline make him the country's most successful individual rower ever. He appeared to have secured his world championship berth with ease at this year's opening World Cup event in Princeton, but the final decision now seems to depend on his readiness to apologise.
Müller was the biggest name missing from this weekend's Swiss rowing championships, held on the same course as the world championships. With Simon Stürm also away, at England's Henley Regatta, it was left to Olivier Gremaud of the Zurich rowing club to take the single sculls title.
There were few surprises in the remaining events, with Caroline Lüthi profiting from a forced withdrawal by Bernadette Wicki to win her eighth women's sculls title in succession.
Nicolas Lätt and Markus Gier had no difficulty adding the Swiss title to their World Cup win in the lightweight double pairs. The two men then teamed up with Adrian Wicki and Silvan Aerni to clinch the lightweight fours title.
Christian Stofer and André Vonarburg also celebrated a double success, beating Martin Urscheler and Florian Stofer in the pairs before joining up with their conquered opponents to take the fours.
swissinfo with agencies