James Tedesco, Tom Trbojevic, Latrell Mitchell and Bradman Best are the first four players named in a prospective World Cup line-up.
The tournament was due to begin in seven days, with teams facing different priorities during the pool stage.
Stronger sides could rotate players, while other nations would need to win as often as possible to reach the next round.
Australia and New Zealand were considered favourites, but England, Tonga and Samoa also had notably strong squads this season.
The preview considers what each nation's strongest 19-player selection might be; the names listed begin with Tedesco, Trbojevic, Mitchell and Best.