EUGENE, Ore. — It will be remembered as the most anticipated race never run. The runoff that turned into a walk away to conclude the US track trials.

Jeneba Tarmoh conceded the final Olympic spot in the 100 meters rather than meet training partner Allyson Felix at the starting line to break a third-place tie. She notified USA Track and Field early in the day of her intention to withdraw from the Monday night race, later saying it was simply because her heart wasn’t into the runoff.

In the original race on June 23, Tarmoh leaned across the finish line and looked up to see her name on the scoreboard in the third spot behind winner Carmelita Jeter and Tianna Madison. The 22-year-old received a medal and held a news conference.

And then she watched the moment evaporate as the race was ruled a dead heat. She was reluctant to take the line for a runoff from the start, especially since she believed she earned the final spot in the 100 fair and square.

‘‘Running in this came down to how I felt internally. Would my heart be at peace running or would I not be at peace? If I was at peace, I would have run,’’ Tarmoh told the Associated Press. “My heart was not at peace with running.’’

USATF president Stephanie Hightower said the organization was ‘‘disappointed’’ that Tarmoh had a change of heart.

Tarmoh said she would not pursue any legal action to get her spot. Tarmoh will be an alternate in the 100 and is also eligible to run in the Olympic 400-meter relay.

Felix will race in both the 100 and 200 in London. She is the favorite to win her signature event, the 200, after winning silver medals in the last two Olympics.