By Gene Cherry
Felix will attempt to become the first woman to win gold at 200 and 400 meters in a world championship next month in South Korea but said a repeat bid at London is not a certainty.
"I would not say it was set in stone ... just because that 200 in London is so important to me," Felix told Reuters in a telephone interview from Los Angeles exactly one year to the start of the 2012 Games.
Although three successive times a winner at 200 meters in the world championships, the versatile sprinter has twice come up short on the Olympic stage.
Jamaica's Veronica Campbell-Brown bested Felix for the gold medal in Athens in 2004 and in Beijing in 2008.
"I have just been waiting for the Olympics to come around again to get an opportunity to tackle that again," she said of the 200 meters.
"Even if it did go well (at the world championships), I am still going to have mixed emotions about (trying for the double in London)."
Felix had previously said she hoped whatever distances she ran at the world championship would be a dress rehearsal for what she did in London. But on Wednesday there appeared to be some doubt in that thinking.
"At the Olympic stage, everything is raised," Felix said. "I think it would be a more difficult path to do it there."
The feat has been accomplished twice. American Valerie Brisco-Hooks did it at the 1984 Los Angeles Olympics and France's Marie-Jose Perec at the 1996 Atlanta Games. (Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Frank Pingue)