Eighth seed American Andy Roddick has pulled out of the Toronto Masters because of illness, the ATP Tour said on Tuesday.
Following a lopsided loss to Frenchman Gilles Simon in the third round of the Washington Classic last week, Roddick had said he felt lethargic and might need time to figure out what was wrong ahead of the US Open.
A winner in Canada in 2003, Roddick's place in the draw will be taken by lucky loser Paul-Henri Mathieu of France.
Chile's Fernando Gonzalez has also withdrawn due to a left calf injury. He will be replaced by Somdev Devvarman of India.
Roddick's departure leaves Sam Querrey and Michael Russell as the only Americans in the main draw.
With the US Open looming, Roddick's illness is more bad news for American tennis which, for the first time since the ATP rankings began in 1973, has no players in the top 10 after Roddick slipped to number 11 after his loss in Washington.