Fringe NRL player Kato Ottio has died at the age of 23 after he suffered "a sudden health issue" in training.
The Papua New Guinea international was due to play for the Widnes Vikings in 2018, signing with the English Super League club after representing his country at the World Cup.
His death was confirmed by Widnes.
"We are devastated to learn that Kato Ottio has passed away this afternoon. Kato was an incredibly talented player, with a bright future ahead of him in rugby league," Vikings chief executive James Rule said.
"This news is all the more tragic, because Kato was due to travel to the UK this week to fulfil his dream of playing first-grade rugby league.
"Having only learned this morning that Kato had developed a sudden health issue whilst training yesterday, we are in absolute shock to now receive this tragic news."
Ottio was an ever-present in the World Cup as the Kumuls topped their group before losing to England in the quarter-finals.
He joined the Canberra Raiders in February 2016 but was unable to force his way into their NRL team.