This week the United States men's basketball team begins preparation for its first major competition since the 2016 Rio Olympics as it starts a weeklong training camp in Las Vegas in advance of the World Cup to be held next month in China.

For the first time in 15 years there is a new coach, Gregg Popovich, and he will have almost a completely new roster. Here's a simple FAQ to catch you up on everything happening with the team.

Q: It seems like a lot of players have dropped out of the competition. Why?

A: Yes, in fact, since the 20-player roster was announced in June, more than a dozen have dropped out, including James Harden, Anthony Davis and Damian Lillard. Several other players who were candidates for the team, such as Kevin Durant and Klay Thompson, are out with injuries.

There are several reasons. First, in this era when rest and recovery have become paramount, playing extra basketball is less of a desire for many players. Second, under the new international basketball schedule, the World Cup and the Olympics are being played in back-to-back summers, and that isn't appetizing for stars who have busy offseasons. Third, the NBA season starts earlier and the World Cup ends later than in years past, squeezing time even more. Fourth, the NBA is sending six teams to Asia this October for exhibition games, and it would've required a number of players, including Harden and Davis, to go twice in a matter of weeks.

Q: Who will be on the team?

A: There is some uncertainty. Training camp followed by two exhibition games will be meaningful in Popovich's decisions. Kemba Walker and Kyle Lowry are locks at point guard, assuming Lowry is recovered from thumb surgery last month.

It appears veteran wings Harrison Barnes, who played on the team in 2016, and All-Star Khris Middleton are likely to make it, with Donovan Mitchell likely as well. There will be strong competition -- including Celtics teammates Jayson Tatum, Jaylen Brown and Marcus Smart -- for the other wing spots. Popovich probably won't take all six, so that should add some intrigue this week.

At the big men spots, it seems likely that veterans Brook Lopez and P.J. Tucker will get strong consideration, with Myles Turner having an ideal skill set for international play as well. Kyle Kuzma, Thaddeus Young, Mason Plumlee and the just-added Bam Adebayo might compete for one or two slots.

Q: Is the U.S. going to win?

A: The U.S. will still have the most talent by far, even with a roster that will be missing many top stars. Not unlike the NCAA tournament, historically international basketball is won with superior guard play. Europe has produced many fantastic big men but not nearly as many top guards, and since the Americans have been sending NBA talent, they have generally won this way.

The last two U.S. losses were guard-play based. In the 2004 Olympics, Manu Ginobili and Pepe Sanchez outplayed a less-than-top-form Stephon Marbury and Allen Iverson. In 2006 at the World Cup, veteran Greek ballhandling expert Theo Papaloukas tore apart a young Chris Paul and an overmatched Kirk Hinrich running the pick-and-roll, and young guard Vassilis Spanoulis had one of the games of his life.

Team USA should still have the most dominating guards in the tournament, especially Walker, who is in position to wreak havoc on inferior competition.

Q: So who will challenge them?

The Americans got a break when Slovenia, the current European champs, didn't qualify. The ballhandling team of Luka Doncic and Goran Dragic would've been a threat.

Team Canada will have the best roster it has ever had, though there are questions regarding whether its backcourt stars will play. Both Jamal Murray and Cory Joseph wavered on their commitments but reported to the team Sunday. They also have the talented Shai Gilgeous-Alexander. The Canadians are coached by the Toronto Raptors' Nick Nurse, who has extensive experience coaching international-style play. But they've suffered losses, too, as Andrew Wiggins and Tristan Thompson decided not to play, and young star RJ Barrett has pulled out because of an injury.

Spain is always competitive and will be again as Marc Gasol, Ricky Rubio and Sergio Llull, one of the best players in Europe, are on the roster. But Pau Gasol, Serge Ibaka, Nikola Mirotic and Sergio Rodriguez aren't playing, so Spain might not be at its best.

A matchup to watch for is a potential meeting between the U.S. and Greece in the second round. Greece has a talented young player you might have heard of named Giannis Antetokounmpo. Just like many of his opponents in the NBA, the Americans really don't have a way to stop him, and in a 40-minute international game in which he is the best player on the floor, anything is possible.

Q: Is there a chance one of the Select Team players could make the roster?

A: Yes. There's a 14-player team that comes to training camp to help the senior roster prepare. In 2014, the last World Cup, Plumlee was promoted from the Select Team to the roster that won gold in Spain.

With Lowry's status uncertain to a degree, there's a good chance one of the Select point guards could make the big team if they play well this week. The strong candidates are De'Aaron Fox and Trae Young. Fox's defense, speed and ability to finish over size are great assets. Young will be one of the best shooters in the gym, and the 3-point shot is vital in international play.

Q: What will the main differences be between Popovich and previous coach Mike Krzyzewski?

A: They are very different coaches with very different styles. One is a college coach whose lead assistant for a decade on the national team was another college coach: Jim Boeheim, whose zone expertise was an asset. Popovich is one of the best pro coaches of all time, and his lead assistant is a former player and champion coach in Steve Kerr. Popovich has much deeper roots in the international game than Coach K did when he first took over, as Popovich has coached numerous international players in San Antonio.

While Krzyzewski was determined to instill respect for opponents, he was a little more resistant to the international game when he started out than Popovich might be. Though Krzyzewski wasn't afraid to be fiery when he needed it, Popovich has a reputation for being gruff and demanding with players.

At the end of the day, they are both Hall of Famers and the team is in good hands.