LAS VEGAS -- USA Basketball managing director Jerry Colangelo said Sunday that he is not worried about the Americans' chances as they begin preparations for the FIBA World Cup, even after a wildly unpredictable process was needed just to fill a training-camp roster for the tournament that starts in China at the end of the month.

"Honestly, I don't have any angst,'' Colangelo said.

After what the two-time defending World Cup champion Americans have been through just to get to camp, that's a very good sign. It took more than 50 invitations -- and probably that many revisions of plans -- to get to Sunday, the day when 15 members of the current national team arrived in Las Vegas for meetings and final preparations before the first training-camp practice under new USA Basketball coach Gregg Popovich starts Monday.

Also in Las Vegas: 14 more NBA players on an enhanced practice squad known as the select team, and it's a very real possibility that some of those players -- Sacramento's De'Aaron Fox probably among them -- will get a good look at moving up to the national team and potentially going to China for the World Cup.

"We're going to have some fun,'' Colangelo said.

It'll likely be a young group going to China, no matter who is on the plane. USA Basketball said at least six of the 12 players on the past three World Cup rosters were age 24 or younger at the time, and that looks like it could be the case again. Of the 15 players on the national team now, six are 24 or younger.

Miami Heat center Bam Adebayo said after arriving in Las Vegas on Sunday that he didn't hesitate when he got the call inquiring about whether he'd want to play.

"I was like, 'Who would say no to this chance?''' the 22-year-old Adebayo said.

Popovich has said finalizing a 12-man roster for China won't be easy. Then again, he likely wasn't counting on this much attrition.

This process of building a team for China started last year with 35 players being added to the selection pool for the World Cup and next year's Tokyo Olympics. Of those 35, 30 have already withdrawn from World Cup consideration for a variety of reasons -- pending fatherhood, injury rehabilitation, filming a movie, preparing for the potential of a long NBA season. The World Cup will end on Sept. 15, meaning the U.S. players, if they made the medal round, would get home about two weeks before NBA camps open.

More than a dozen other names were officially added to the national team list along the way, with two of those players dropping out already, as well. Others, such as New Orleans' J.J. Redick, were invited but declined even before being formally added to the list.

Add it all up, and there have been at least 52 players under real consideration in the past year and a half. That doesn't include the select-teamers, others who were considered for that squad such as New Orleans rookie and No. 1 overall draft pick Zion Williamson (who declined) or the 52 G League players who went through 12 qualifying games needed to get the U.S. into the World Cup.

"The focus has to be on who's here -- not who's not here,'' Colangelo said. "A number of the young players in this group have a chance, a real chance, some of them to make this team, some of them to make an impact in the World Cup.''

NOTES: Kyle Lowry of the NBA champion Toronto Raptors is in Las Vegas but still has not been cleared to play following thumb surgery. He's scheduled to meet with doctors in the coming days and hopes to participate when the second part of camp shifts to El Segundo, California, next week. ... The team will practice Monday through Thursday, then scrimmage Friday. ... Colangelo said NBA free agent Carmelo Anthony, who has been a USA Basketball standout in the past, was not considered for the World Cup roster.