LAS VEGAS (AP) - Mike Krzyzewski was already down two players even before he ran his first practice.
There's still plenty more he needs to evaluate.
The Americans opened training camp Tuesday, giving the Hall of Fame coach and his staff their first chance to look at the 20 players competing for spots in the world championships.
"It is wide open, and this is good. It shows they want to be here, they want to be a part of USA Basketball," Krzyzewski said of the large turnout. "These five days are extremely important for us to evaluate.
"What we need to do is to figure out a core eight or nine, and then (determine) who complements those eight or nine in style."
One of them was expected to be Amare Stoudemire, but he was forced to withdraw before camp opened because of problems insuring his new contract with the New York Knicks. Phoenix Suns center Robin Lopez also pulled out to continue rehabilitating a back injury he sustained late in the regular season.
The remaining players will work out at the UNLV campus through Saturday, and the roster will likely be trimmed before the team resumes workouts next month in New York.
"That's why this week is so important to us to watch them compete, practice," USA Basketball chairman Jerry Colangelo said. "We told them it's wide open, and that we would probably go to New York with 15. So we're starting this morning with 20. Amare is out, Robin Lopez is out, so the first week will determine who the 15 are and we'll go from there."
Krzyzewski, the coach of national champion Duke and the 2008 gold-medal winning U.S. team, welcomed back his entire staff of Syracuse coach Jim Boeheim, Knicks coach Mike D'Antoni and Portland Trail Blazers coach Nate McMillan. Colangelo, who built the national team program, also returned.
The players, however, are a different story. LeBron James, Kobe Bryant, Dwyane Wade and the rest of the Olympic champions are taking the summer off, so the Americans will rely on the few players who do have international experience.
"We have some experience with Chauncey Billups and Lamar Odom, but we have got a lot of young guys," D'Antoni said. "And Kevin Durant played with us a couple years ago on the select team. So most of the guys have a little bit of experience, and they'll do well.
"We have got a good thing going. We have a lot of players here who want to play, which is cool. Some of the best players in the NBA are here. They're young, but they're really talented basketball players. So the team should be real good."
The rest of the players in camp are: Rajon Rondo (Boston Celtics), Derrick Rose (Chicago Bulls), Tyson Chandler (Dallas Mavericks), Stephen Curry (Golden State Warriors), Tyreke Evans (Sacramento Kings), Rudy Gay and O.J. Mayo (Memphis Grizzlies), Eric Gordon (Los Angeles Clippers), Danny Granger (Indiana Pacers), Russell Westbrook and Jeff Green (Oklahoma City Thunder), Andre Iguodala (Philadelphia 76ers), David Lee (Golden State Warriors), Brook Lopez (New Jersey Nets), Kevin Love (Minnesota Timberwolves), Gerald Wallace (Charlotte Bobcats) and JaVale McGee (Washington Wizards).
Lee injured the middle finger on his right hand during practice and returned to California to have it looked at by the Warriors' team doctors. He is expected to return to camp Wednesday.
The 12 players who are picked for the final roster in Turkey will try to help the Americans win the world championships for the first time since 1994 and earn an automatic berth into the 2012 Olympics.
"The main thing is to win the world championship," Krzyzewski said. "There are 24 teams that compete for this and only 12 that compete for the Olympics. We're part of the world and we should look at it like they're looking at it. That's what we learned over the last four years."
Another thing that Krzyzewski hopes to learn this week is how his players jell together.
"The guards are one of our strengths, and the ability to put ball pressure on for 40 minutes," he said. "So that's the thing we are going to be looking at, are what (guard) combinations can they play together really well. They're all accustomed to having the ball a lot."
With a deep collection of wing players, the Americans will likely look to push the pace.
"It's a young man's game, and we have a lot of young legs here, no question about that," Colangelo said. "That's another feature of this team."