The 20-player roster, to which Ramos will add one player by the May 15 deadline, comprises of seven MLS players, eight European-based, two from Liga MX, one from the Argentine league, one collegian and one player without a club.
Among the omissions is Columbus Crew midfielder Romain Gall, who was co-leading scorer with five goals in the Concacaf qualifying tournament, where he appeared in five of the six games as the USA finished third. He also scored the winner in a 1-0 friendly victory over Croatia April 25 after returning to action following a minor knee injury that sidelined him for the early part of the MLS season.
Forward Rubio Rubin, who has made three appearances for the full national team, is on the squad after not being released by his Dutch club Utrecht for the qualifying tournament.
Ramos did not call in German product Julian Green, who has not played for the U-20s but scored a goal for the USA at the 2014 World Cup in Brazil. He has languished on the bench at Hamburg SV this season while on loan from Bayern Munich.
Ramos’ leaving one spot open is because U.S. Soccer is waiting for FIFA to rule on the eligibility of 18-year-old, German-born midfielder Gedion Zelalem, who plays for Arsenal’s reserve team. If Zelalem is not cleared, Zach Pfeffer of the Philadelphia Union will be the 21st player.
The USA, which is aiming to reach the knockout stage of the biennial competition for the first time since 2007, faces Myanmar, host New Zealand and Ukraine in group play at the U-20 World Cup May 30-June 20.
"I'm very excited about this particular group," said Ramos. "It was very difficult making the final decision because there were quite a few players who deserved to go to the World Cup. Unfortunately, in the end I can only select a certain number, and I'm very happy with the selections that we made."
USA U-20 World Cup roster
GOALKEEPERS (3): Jeff Caldwell (University of Virginia; Todd, N.C.), *Ethan Horvath (Molde FK; Highlands Ranch, Colo.), *Zack Steffen (Freiburg; Downingtown, Pa.) .
DEFENDERS (6): *Cameron Carter-Vickers (Tottenham Hotspur; Westcliff on Sea, England), *Matt Miazga (New York Red Bulls; Clifton, N.J.), *Shaquell Moore (Unattached; Powder Springs, Ga.), Erik Palmer-Brown (Sporting Kansas City; Lee's Summit, Mo.), Desevio Payne (FC Groningen; Greenwood, S.C.), *John Requejo (Tijuana; Carpinteria, Calif.).
MIDFIELDERS (6): *Kellyn Acosta (FC Dallas; Plano, Texas), *Paul Arriola (Tijuana; Chula Vista, Calif.), *Russell Canouse (Hoffenheim; Lancaster, Pa.), Marco Delgado (Toronto FC; Glendora, Calif.), *Emerson Hyndman (Fulham; Dallas, Texas), Joel Soñora (Boca Juniors; Buenos Aires, Argentina).
FORWARDS (5): Jordan Allen (Real Salt Lake; Rochester, N.Y.), *Bradford Jamieson IV (LA Galaxy; Los Angeles, Calif.), Rubio Rubin (Utrecht; Beaverton, Ore.), Maki Tall (Red Star; Washington, D.C.), *Tommy Thompson (San Jose Earthquakes; Loomis, Calif.).
*On qualifying roster.