Nine of the players were part of the USA's 2013 U-20 World Cup team: Cody Cropper, Luis Gil, Alonso Hernandez, Benji Joya, Juan Pablo Ocegueda, Shane O'Neill, Mario Rodriguez, Oscar Sorto and Jose Villarreal.
Eleven players were on the squad that defeated Bosnia's U-23 team 5-2 on March 27, including all five U.S. goalscorers from that game: Fatai Alashe, Morris, Rodriguez, Joya and Hernandez. Other players returning from that roster are Christian Dean, Ocegueda, O'Neill, Sorto, Gil, and Alfred Koroma Shams.
Cropper, Dean, Gil, Kempin, Morris, O'Neill, Serna and Sorto have all been part of a USMNT senior camp this year.
Herzog is preparing the team for the 2015 Concacaf Olympic qualifying championship that will be played in the United States Oct.1-13.
U.S. U-23 men’s roster
GOALKEEPERS (2): Cody Cropper (Southampton; Maple Grove, Minn.), Jon Kempin (San Antonio Scorpions; Leawood, Kan.).
DEFENDERS (8): Christian Dean (Vancouver Whitecaps; East Palo Alto, Calif.), Juan Pablo Ocegueda (Alebrijes de Oaxaca; Riverside, Calif.), Boyd Okwuonu (Real Salt Lake; Edmund, Okla.), Shane O'Neill (Colorado Rapids; Boulder, Colo.), Dillon Serna (Colorado Rapids; Brighton, Colo.), Oscar Sorto (LA Galaxy; Los Angeles, Calif), Sam Strong (UC Santa Barbara, Santa Barbara, Calif.), Walker Zimmerman (FC Dallas; Lawrenceville, Ga.).
MIDFIELDERS (5): Fatai Alashe (San Jose Earthquakes; Northville, Mich.), Luis Gil (Real Salt Lake; Garden Grove, Calif.), Alejandro Guido (Club Tijuana; Chula Vista, Calif.), Benji Joya (Santos Laguna; San Jose, Calif.), Daniel Metzger (New York Red Bulls II; Holmdel, N.J.).
FORWARDS (5): Alonso Hernandez (C.F. Monterrey; El Paso, Texas), Alfred Koroma Shams (Unattached; Southlake Carol, Texas), Jordan Morris (Stanford; Mercer Island, Wash.), Mario Rodriguez (Borussia Mönchengladbach; North Hollywood, Calif.), Jose Villarreal (LA Galaxy; Inglewood, Calif.)