Jeneba Tarmoh has declined the opportunity of a run-off with Allyson Felix for the final women's 100 metres berth in the United States' Olympics team.
The pair could not be split as they finished joint third in 11.07 seconds in the 100m final at the trials in Eugene on June 23.
With no formal policy on how to deal with such a situation, it had been unclear whether the issue would be decided by a race or the toss of a coin until the head-to-head was scheduled for 1700 Pacific Time (0100 BST this morning).
Having considered that option, Tarmoh wrote to the USA Track and Field president and chairman Stephanie Hightower standing down.
An email released by the athlete's agent Kimberley Holland read: "I Jeneba Tarmoh have decided to decline my third-place position in the 100m dash to Allyson Felix.
"I understand that with this decision I am no longer running the 100m dash in the Olympic Games and will be an alternate for the event. As an alternate I understand that I will be asked to run if another 100m runner decides not to for personal reasons, and/or on the 4x100m relay."
Felix now joins qualifying winner Carmelita Jeter and second-placed Tianna Madison.
