Jeff Horn's trainer Glenn Rushton doubts a rematch with Manny Pacquiao will eventuate.
Horn won his WBO welterweight title with a controversial unanimous decision victory over Pacquiao last July at Suncorp Stadium.
The Filipino great had indicated his willingness to fight Horn again almost immediately afterwards but, eight months later, it looks less likely than ever.
Top Rank promoter Bob Arum had planned for the winner of Horn's mandatory title defence against Terence Crawford on April 14 in Las Vegas to square off against Pacquiao, who was slated to fight Mike Alvarado on the same card.
Arum's hope was that Crawford would win and then face Pacquiao in a marquee fight designed to 'pass the torch' to the unbeaten American.
But Pacquiao, 39, rejected the offer, which his media relations officer called an "insult" to the former eight-division world champion.
It's unclear what his next move will be - but Rushton anticipates it will have nothing to do with Horn.
"We're up for it but, honestly, we don't think Manny Pacquiao's up for it," he told AAP.
"They had their opportunity; they could have come straight back and done the rematch.
"If you really thought you could do it, you would have done it then.
"Realistically, as much as we'd welcome the fight, the chances of Manny Pacquiao fighting Jeff Horn again I think are slim to none."
Pacquiao cited a schedule clash with his political duties as the reason why he couldn't take up the Horn rematch.
Horn has moved on, Rushton says, and is deep in preparations for the Crawford bout - his first outside Australia and New Zealand.
Rushton called it the "biggest fight of the year", even though it was struggling to gain traction in the United States.
"People think he's a certain winner. We're saying, 'no, you don't get this'," he said.
"People just haven't really acknowledged Jeff. I know it eats a little bit at him.
"This is going to be another huge war - a really, really tough, hard, close fight.
"We've got the best pound-for-pound in the world against a guy who's done just incredible things.
"How many guys have fought as many world-ranked fighters as Jeff in their first 19 fights? You'll be struggling to find one."