Racing Victoria chief steward Terry Bailey may quit if Danny Nikolic wins back his jockey licence.
Bailey argues the position between himself and Nikolic is untenable and cannot work, should a tribunal overturn Racing Victoria's decision to reject the jockey's application to be relicensed.
"If Danny Nikolic was to be given a licence, well he is given a licence," Bailey told the appeal on Friday.
"Maybe it will be me that will have to move on."
Nikolic has said he may move to Queensland to get out of "the firing line of Terry Bailey and his henchmen" if he succeeds in being relicensed as a jockey after four years on the sidelines.
Nikolic still denies threatening Bailey in the incident that led to him being outed from racing and has accused the steward in court of being corrupt and a liar.
Bailey said it would be very, very difficult for him and the rest of the stewards to work with Nikolic.
"Our position is untenable," he repeatedly told the Victorian Civil and Administrative Tribunal.
"Our position between Danny Nikolic and the stewards can't work."
Pressed by Nikolic's barrister Julian Burnside QC if he would do his best to work with the jockey should he be relicensed, Bailey maintained it would be very difficult.
He said the stewards "don't look for trouble" and were professionals.
"We will do what we do every day of the week at the races.
"I would do what I am paid to do and do the job to the best of my ability."
Nikolic was outed for two years for threatening Bailey at a September 2012 race meeting before copping a further one-year suspension for offensive conduct towards another steward.
Nikolic had neither apologised for the Seymour incident nor withdrawn the threat, Bailey said in a statement to VCAT.
"In circumstances where Mr Nikolic has neither expressed any remorse over the incident at Seymour nor withdrawn the threat to my family, I still take the threat he made to me very seriously."
Nikolic has denied threatening Bailey and telling him "we all have families and I know where yours lives", accusing the steward of lying about the threat.
He said Bailey threatened to destroy his career, which the steward denied.
"It's just all a big fat lie," Bailey said.
Bailey acknowledged there was tension between himself and the Caulfield Cup-winning jockey throughout the Betfair inquiry.
Nikolic was cleared of serious racing charges related to lay bets placed via Betfair on a number of his rides between October 2009 and February 2010.
Bailey denied telling a fellow steward "don't worry, we'll get him for something" after the Racing Appeals and Disciplinary Board cleared Nikolic.
Nikolic's appeal will return to VCAT for a sixth hearing day on October 19 as Racing Victoria seeks to force jockey Mark Pegus to give evidence about a 2011 altercation with Nikolic, and to hear final submissions.