Jeff Horn has his doubts over whether the hand injury that prompted Terence Crawford to postpone their WBO welterweight title clash ever happened.

Horn's promoter Dean Lonergan alleged last month that Crawford's bruised right hand was a "fake injury" concocted by his camp and Top Rank boxing to push back the fight for financial reasons.

The June 9 bout in Las Vegas will be screened on the new ESPN streaming app, which wouldn't have been ready had it gone ahead on the original April date.

Lonergan asked Crawford's camp to provide medical evidence to prove the injury actually happened, but it was not provided.

There are also suggestions Crawford wanted more time to prepare after discovering how good Horn looked in training.

"Hopefully he doesn't watch me anytime soon and get too scared. It might get postponed again," Horn said.

"I don't know why they postponed last time but whatever happens, happens. I've had friends tracking him on Instagram and Facebook and whatever.  He seemed to be bowling and using that hand quite fine (for a guy) with a hand injury."

The fight originally was scheduled for April 14.

However, Horn is convinced the delay has actually worked in his favour.

"I'm on track, that's for sure," Horn said.

"I'm feeling as fit as I've ever felt because it's basically a double prep for me. I'm in the best shape at the moment and I think I'm going to be very, very strong at welterweight."

Horn and his trainer, Glenn Rushton, remain bullish about their chances of snapping Crawford's unbeaten streak despite being rank underdogs for the Las Vegas showdown.

Crawford, the 30-year-old from Omaha, Nebraska, is regarded as one of the world's best pound-for-pound fighters and has won 23 of his 32 fights by knockout.

For Horn, this is his second defense of the title after stunning Manny Pacquiao last July in Brisbane, Australia.