Jeneba Tarmoh has conceded her spot in the 100 meters rather than race against training partner Allyson Felix.
Tarmoh notified USA Track and Field on Monday of her intention to withdraw. Her agent, Kimberly Holland, already made it known that Tarmoh would not participate in a runoff Monday night to break a third-place tie at the U.S. track trials.
In an email sent through her agent to USATF, Tarmoh said: "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."
USATF President Stephanie Hightower said the organization is "disappointed" Tarmoh had a change of heart.
