in the running
Entered as a competitor in a contest. For example, Is Mary in the running for this election? The antonym, out of the running, means "not entered as a competitor," as in Ian is out of the running for the job now that he's living in another state. [Mid-1800s]
Having a chance to win, as in Mary's still in the running for the promotion. Again, out of the running means the opposite, as in He's too old
he's out of the running. [Mid-1800s] Both usages allude to the entry and chances of a horse in a race.