Organizers of the Lausanne Diamond League meeting say United States sprinter Justin Gatlin has ended his season early because of illness.
Gatlin was due to run at the Athletissima meet in Switzerland on Thursday, with the competition to be streamed live on CBCSports.ca, at 2 p.m. ET.
Gatlin was treated for stomach pains and fever at a hospital in Austria this week.
Athletissima organizers say in a statement that "his situation has not improved."
They say Gatlin "has taken the decision to return to the USA, withdrawing from the meeting in Lausanne as well as ending his season."
Gatlin was the 100-metre bronze medallist at the London Olympics this month, and helped the U.S. to silver in the 4 X 100 relay.
Gatlin won the 100 metres at the 2004 Athens Games, making him the only man to land on the podium in the event eight years apart.
He wasn't at the Beijing Games due to a four-year doping ban.
Gatlin on Thursday was scheduled to face two-time Olympic silver medallist Yohan Blake of Jamaica and American teammate Tyson Gay, who placed fourth in London in the fastest collective 100 race ever held.
Olympic champion Usain Bolt has opted to run the 200 on Thursday.