United States U20 head coach Tab Ramos has a lot of decisions to make ahead of the U20 World Cup in South Korea in May.

Twenty-one to be exact.

While Ramos did well enough with the 20-player squad he took to Costa Rica to qualify for the World Cup and hoist the CONCACAF U20 trophy, he did so without several European-based players he could call on for his 21-player World Cup roster.

He also did it without a domestic player who made waves in his Major League Soccer debut on Sunday in Philadelphia Union midfielder Derrick Jones.

The 20-year-old Ghana native was unavailable for selection to go to Costa Rica but is expected to have his paperwork cleared to be eligible to represent the U.S. in an official capacity at the World Cup.

“We filed his paperwork to get him approved for World Cup qualifying, but it was two weeks too early because his papers could only be accepted March 5 and FIFA didn’t give us an exception, so we re-applied yesterday to FIFA,” Ramos said in an interview with SoccerAmerica.

Jones moved to the U.S. at age 14 and joined the Philadelphia Union Academy in 2013 after he was discovered while playing for local club Junior Lone Star FC. Ramos called him up twice last year for the Four Nations Tournament in England in September and for a training camp in Costa Rica in December.

“He’s a player who could potentially be important to the team if he’s doing well,” Ramos added.

Berlin, New Jersey native Isaiah Young is likely to be among the European-based players in consideration. Young, who spent a season playing for the Union U16s, is currently playing in Germany with Werder Bremen’s U19 team. European-based players like Cameron Carter-Vickers, Weston McKennie, Nick Taitague, Haji Wright and Joshua Perez are also firmly on Ramos’ radar.

If Carter-Vickers is cleared to play by Tottenham, it would likely limit the chances of another Union player in Auston Trusty going to South Korea. Trusty made two appearances in Costa Rica - his only start coming at left back - and that was with Erik Palmer-Brown moved from central defense to the midfield. Justen Glad and Tommy Redding started every match of the tournament in central defense. Former Lehigh Valley star Daniel Barbir, who is with West Brom in England, could also be an option in central defense.

The U20 World Cup will take place May 20-June 11 in South Korea. Rosters should be announced some time in early May.