It is the second time in three weeks he has had to withdraw from a tournament with the same injury. The world No 9 also withdrew from a hard-court event in Los Angeles. It is the same injury Rusedski had at the French Open in May, and raises questions about his long-term fitness.
The British No 2 was bothered by injuries in the other two Grand Slam tournaments this year - the Australian Open where he had a bad back while losing to America's Paul Goldstein, and Wimbledon where he needed treatment for a bad thigh when losing to Australia's Mark Philippoussis.
The continuing toe problem also places at risk Rusedski's build-up for the US Open, which starts at Flushing Meadow in New York in less than three weeks' time - a tournament in which he was a finalist two years ago. He is still entered for the RCA Championships at Indianapolis and hopes to begin his American hard-court campaign there next week.
Martina Hingis celebrated her return to the world No 1 position by beating Venus Williams 6-4, 6-0, on Sunday, to win the TIG Classic in Carlsbad, California.
Williams, in disposing of Lindsay Davenport in the semi-finals, ensured that Hingis would recapture the top spot if she got to the final.Reuse content