It’s understood USA Basketball still has hopes one or both could play with Williamson potentially joining other young stars on the Team USA select team who will be named in the coming weeks and will join the other players for camp.
Damian Lillard, CJ McCollum, Jayson Tatum, Donovan Mitchell and Andre Drummond have also put their hands up to play as have Kyle Lowry, Bradley Beal and Kemba Walker.
For the last World Cup in 2014, the USA selected a number of rising young stars between 21-25 – including Curry, Harden and Davis – but this roster is noticeably older with the likes of PJ Tucker, Paul Millsap, Brook Lopez and Lowry named.
The 20 players named and any late inclusions will form the 12-man squad who will play against Australia for two games at Marvel Stadium in late August and a clash with Canada in Sydney before flying to China for the World Cup.
New USA coach Gregg Popovich will take charge of the national team for the first time and he expects great difficulty in naming a final roster.
“I am excited about getting to training camp in August and working with all of the players that have been selected to attend the USA national team training camp in Las Vegas,” Popovich said.
“We’ve got an excellent cross-section of veteran USA Basketball and NBA players, as well as some exciting younger players who possess amazing versatility.
“I’m appreciative of commitment that our national team players continue to make, and the eagerness of the new players to become involved. Selecting a 12-man team will be extremely difficult.”
Team USA players will compete in a Blue versus White exhibition game in T-Mobile Arena, Las Vegas on August 9 at the end of their training camp.
They will train in Los Angeles on August 13-15 then take on Spain at the Honda Centre in Anaheim on August 16, with the World Cup side to be named on August 17.
That roster will then fly to Australia and train in Melbourne from August 19-24 including the two showdowns with the Boomers at Marvel Stadium on August 22 and 24.
The USA will complete their World Cup preparations in Sydney and play Canada at Qudos Bank Arena on August 26.
The FIBA World Cup begins on August 31 and runs until September 16.
Team USA selection squad for 2019 FIBA World Cup: Harrison Barnes, Bradley Beal, Anthony Davis, Andre Drummond, Eric Gordon, James Harden, Tobias Harris, Kyle Kuzma, Damian Lillard, Brook Lopez, Kevin Love, Kyle Lowry, CJ McCollum, Khris Middleton, Paul Millsap, Donovan Mitchell, Jayson Tatum, P.J. Tucker, Myles Turner, Kemba Walker. Coach: Gregg Popovich. Assistant coaches: Steve Kerr, Lloyd Pierce, Jay Wright.
Roy Ward is a Sports writer for The Age.