From my track experience, no one ever says runners could be in an upcoming race. They say: 'person A, person B , etc... are in the 800m, person C, person D, etc... are in the 400m'
No one ever says 'OK, for the next race here are the possible runners. Or, the following people could be in the 800m, who knows for sure? Maybe a meteor will fall on us all in 10 seconds and there won't be a race.' - not a typical day at the races quote.