Distressed AFL footballer John McCarthy told his girlfriend he wanted to return home just hours before falling to his death at a Las Vegas hotel.

McCarthy told his girlfriend he was heading to the airport after becoming separated from his Port Adelaide teammates on an end-of-season trip to the US.

The Las Vegas coroner says there doesn’t appear to be any suspicious circumstances surrounding the 22-year-old’s death other than that he did not die of natural causes.

Clark County Coroner Mike Murphy said McCarthy fell about nine metres from a roof at the Flamingo Hotel, but there were no signs of any foul play.

“There’s nothing that indicates this is a homicide so now we’re investigating this as either an accident or a possible suicide,” Mr Murphy told AAP on Tuesday morning.

He stressed that he was not saying it was a suicide, just that it was being investigated.

McCarthy was found on the driveway of the Flamingo Hotel about 5.40am on Sunday, Las Vegas time – some four kilometres from the hotel where he was staying.

“It’s a bit weird… it makes it all the more baffling,” Port Adelaide chief executive Keith Thomas told Fairfax Radio.

About two hours before his death, McCarthy telephoned his girlfriend Dani Smarrelli in Adelaide, sounding confused and saying he wanted to return home, Smarrelli has told Port officials.

She said she was unsuccessful in trying to contact the other Port players after McCarthy’s call.

McCarthy’s 10 teammates in Vegas were unaware he had died until informed by Port officials hours after the fatality.

Port players who were with McCarthy earlier said he was enjoying himself before they became separated, Mr Thomas said.

“Our players weren’t there so they don’t really know anything more than that other than that he was having a good time whilst he was with them,” he said.

“All we know is that he was at the Flamingo casino, he was on his own.”

McCarthy left Collingwood, where he played 18 games over four seasons, late last year and joined Port Adelaide, where he played 21 games this season.

New Carlton coach Mick Malthouse paid tribute to McCarthy, who he coached for four years at Collingwood from 2008-11.

“It does put things in perspective,” Malthouse said at a media conference announcing his appointment as Blues coach.

“It’s one of those moments where you come to realise being an AFL footballer doesn’t give you an immunity to tragedy.

“A lot of boys would like to think they wear a Superman suit around but unfortunately that’s not the case and it brings things back to reality.

“It is with a very heavy heart – and I sincerely mean that, I coached John for a number of years and had a lot to do with his family.”

While an autopsy has been completed, Mr Murphy said it would be eight to 12 weeks before results from toxicology tests were known.

Police said they would retrace McCarthy’s steps to try to determine where he was before the incident, who he was with and who else was around at the time.

“This will not come to a conclusion until an autopsy report is generated and toxicology and other laboratory reports come back,” Las Vegas Metropolitan Police officer Laura Meltzer told reporters.

The AFL says there will be a minute’s silence before each of this weekend’s semi-final matches as a mark of respect for McCarthy.