USA Baseball 18U National Team manager Rob Cooper and his staff of more than 25 evaluators at the Tournament of Stars had a difficult job this week.

And it only gets tougher from here.   

USA Baseball and Cooper's staff announced the 40 players who will attend the 18U National Team Trials in mid August in Los Angeles, where they will select the 20 who will compete in the IBAF 18U World Cup in Taichung, Taiwan, Aug. 30-Sept. 

Team USA won the gold medal at last year's IBAF 18U World Championships.

Of the 40 players selected, 38 were among the 144 who participated in the Tournament of Stars, a five-day event at the USA Baseball National Training Complex that ended Sunday. Five of the 38 players were selected from last fall's National Team Identification Series.

Ten alternates were also selected.

The group includes one returning 2012 gold medalists: Bryson Brigman, an infielder from San Jose, Calif., who has committed to Stanford.

"This has been an unbelievable group from a talent standpoint, or otherwise they wouldn't be here," Cooper said. "But, more importantly, you can tell how much it means to these guys to be a part of the National Team.

"They're working, they're trying, they're playing hard. The times you do coach them up they listen to it.

"Unfortunately we only get four games, we only get one week, and there are going to be some guys who don't move on who will play in the big leagues someday.

"It's been a difficult process, but a very good one."

USA Baseball continues to improve the process, including changes to skills assessment day on Friday. Players got to choose their primary position group, and the evaluation staff was able to see them among peers.

But that was not the only benefit.

"We got to interact with guys a little bit more," Cooper said. "We got to control it and hit some ground balls and do some things that allowed us to be able to answer some questions, and also just really see their overall attitude.  

"When a guy came in, was he complaining that he had to do that? Or was it something they wanted to be a part of?

"It was really helpful."

The Tournament of Stars meant long days for Cooper and the evaluation staff, but there were few complaints.

"It's baseball Nirvana if you're a coach," Cooper said. "You're doing this for the USA Baseball program, so that right there fires you up. But the baseball knowledge and the passion these guys have, you've got all these baseball people who just know the game and bring so much insight.'

Through the week, Cooper said there were few surprises.

"I wasn't surprised about the talent, because I knew it would be great players," he said. "I wasn't surprised by the coaches helping us, because they are great coaches.

"I think the thing that stuck out to me was just how open players were to making adjustments and changing positions, to show their versatility because they want to be a part of it.

"And I'd have to say the weather (dry and in the mid 80s) surprised me. I think everybody around here would say that right now."

The next phase, in Los Angeles, is more difficult, Cooper said.

But he said that's as it should be.

"You're talking about going from the 40 best players to the 20 best players in the country in their age group," he said. "So it should be tough."

There's also the little matter of defending a gold medal. But Cooper said it's even bigger than that.  

"This is our national pastime, this is our sport, and we are representing our country," he said.

"To me, we owe it to the guys who wore the USA uniform before us to put together the best team and to give our best effort going forward.   

"If we do, we will put ourselves in position to win a gold medal."

The following 40 players were named to the 2013 USA Baseball 18U National Team Trials:

Name, Position, Hometown (in alphabetical order)

Brady Aiken, LHP, Cardiff by the Sea, Calif.
Bobby Bradley Jr., IF, Gulf Port, Miss.         
Bryson Brigman, IF/OF, San Jose, Calif.      
Quinn Brodey, LHP/OF, Los Angeles, Calif. 
Griffin Canning, RHP, Coto De Caza, Calif. 
Bryce Carter, C, Tulsa, Okla.
Zachary Carter, IF/RHP, Arlington, Texas    
Ryan Castellani, RHP, Phoenix, Ariz.           
Denz'l Chapman, OF, Los Angeles, Calif.     
Braxton Davidson, IF/OF, Arden, N.C.         
Joe DeMers, RHP, Martinez, Calif.   
Alex Destino, LHP/OF, Weaverville, N.C.     
Christian Donahue, IF, Mililani, Hawaii          
Devon Fisher, C, Portsmith, Va.        
Jack Flaherty, IF/RHP, Burbank, Calif.        
Brian Gonzalez, IF/LHP, Miramar, Fla.         
Marvis Gorgas, RHP/IF, East Hampton, Conn. 
Adam Haseley, OF/LHP, Windermere, Fla.  
Derek Hill, OF, Sacramento, Calif.   
Scott Hurst, OF, Glendora, Calif.      
Kel Johnson, OF, Palmetto, Ga.       
Tyler Kolek, RHP, Shepherd, Texas 
Turner Larkins, RHP, Arlington, Texas         
Trace Loehr, IF, Milwaukie, Ore.       
Mac Marshall, LHP, Parkview, Ga.   
Keaton McKinney, RHP/IF, Ankeny, Iowa    
Brandon Murray, RHP, Hobart, Ind.  
Jacob Nix, RHP, Los Alamitos, Calif.           
Luis Ortiz, RHP, Sanger, Calif.          
Jakson Reetz, C/OF/RHP, Hickman, Neb.  
Sean Reid-Foley, RHP, Jacksonville, Fla.    
Michael Rivera, C, Venice, Fla.         
JJ Schwarz, C, Palm Beach Gardens, Fla.  
Justus Sheffield, LHP, Tullahoma, Tenn.      
Lane Thomas, OF, Knoxville, Tenn.  
Cole Tucker, IF, Phoenix, Ariz.         
Jeremy Vasquez, IF/OF, Palm City, Fla.      
Chris Viall, RHP, Santa Cruz, Calif.     
Logan Warmoth, IF/OF, Longwood, Fla.       
Keith Weisenberg, RHP, Seminole, Fla.