Non-runner
A dog declared for a race but withdrawn before the off. Selections on a non-runner are voided and any allocation returned.
A non-runner (NR) is a greyhound that was declared for a race but is withdrawn before the traps open. Withdrawal can happen for various reasons: a late veterinary issue, weight check failure, or kennel withdrawal.
Settlement in racing markets: a wager on a non-runner is voided and the allocation is returned. Forecast and tricast wagers typically deduct the non-runner using Rule 4 (a percentage deduction from the remaining dogs' prices proportional to the NR's market price).
On TrapStats: every settled selection whose runner was withdrawn is recorded with status non_runner and bet_return = 0. The Denis live tracker explicitly checks for NRs before logging the selection (a placement-time snapshot guards against the trap being rebound to a different dog between selection and result).
When you look at the recent results panel and see a dog with no finish position and nr on the line, that's the explanation.