I know he's not currently a citizen, but I believe he's on the path. http://www.startribune.com/sports/blogs/218223771.html
Looks like he made it: So proud to finally be a US Citizen! #finally God bless America!— Ruben Luna (@RubenLuna34) July 13, 2015 He plays for Inter Playa FC in Mexican 2nd Division (level 3). He was previously with the Atlanta Silverbacks, but not sure when he left. http://www.interplayafc.com/content/15/equipo @bungadiri -- let's change title to "Ruben Luna at Inter Playa FC" and move to the YA Academy. H/T to @Clint Eastwood for finding this.