ODDS ARE THAT the Mexico under-23 team knows to keep a close eye on Jordan Morris.

United States U-23 and Olympic coach Andreas Herzog has included Morris, a Stanford sophomore who last week scored for the U.S. senior team against Mexico, in the 20-player roster he announced today for Wednesday’s friendly against its Mexican counterparts at the StubHub center in Carson, Calif.

Morris, who famously turned down a homegrown contract from Seattle last winter to continue his education but burst onto the national soccer conscience with his well-struck game-winner last week, is part of an eclectic roster that includes 10 players from MLS rosters (one of whom is on loan to the second division San Antonio Scorpions); four players based in Mexico; two from European clubs; and a youngster who will be starting his collegiate career in the fall. Here's the full squad:

GOALKEEPERS

Cody Cropper (Southampton; Maple Grove, Minn.), Jon Kempin (San Antonio Scorpions; Leawood, Kan.)

DEFENDERS

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

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

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.)

The roster is very reliant on the 2013 U.S. U-20 World Cup team, with nine players from that team taking part. Luis Gil is the likely leader of the team as the heavily experienced Real Salt Lake midfielder has been a stalwart of U.S. youth national teams dating back to the 2009 U-17 team. Gil and Morris are the only players on this roster who have been capped by the senior U.S. national team.

The Colorado Rapids’ duo of Shane O’Neill and Dillon Serna, who scored MLS’ goal of the week nine days ago, and the Los Angeles Galaxy’s Jose Villareal, who began the season with a goal and two assists, are among the U-20 World Cup veterans on this squad.

Since the game is not on a FIFA international date, many age-eligible players in Europe were not available for the game. Such players include John Brooks and DeAndre Yedlin. Also, with the U.S. U-20 team currently assembled in Austria, the best players from that squad were also not available.

Men’s soccer is a U-23 event at the Olympics and the U.S. will look to qualify for next year’s games in Rio di Janeiro in this fall’s CONCACAF U-23 tournament, the semi-finals and finals of which will be played in October at Real Salt Lake’s Rio Tinto Stadium. This will be the second camp for the United States U-23 team since Herzog was named coach. Last month in Europe he led his troops to a 5-2 win over Bosnia but the team fell to Denmark 1-0.

Sam Strong qualifies as the most curious inclusion on this roster by virtue of the fact that he will start his college soccer at nearby U.C. Santa Barbara this fall. A six-foot-one center back, Strong was born in 1996 and is age-eligible for the current U.S. U-20 national team but has never been called in to any camp by U-20 coach Tab Ramos.

Strong was selected over defender Brandon Vincent, Morris’ teammate at Stanford and a first-team All-American last year for the Cardinal.

Another curious inclusion: Forward Alfred Koroma, a former youth star from Texas who was recently with the third division Austin Aztez but is currently without a club after reaching, according to the USL, a “mutual termination agreement.” Koroma came through U.S. soccer’s youth residency program in Bradenton, Fla. and played two seasons of lackluster college soccer, first at Akron then at Southern Methodist, starting a combined 14 games (out of 31 total) and scoring just seven goals.

Koroma tried turning pro in 2014 but after failing to catch on with teams in Brazil he signed with Austin and had yet to play for the team before parting ways Saturday.  

Dan Metzger, the former Maryland star whom New York Red Bull declined to offer a homegrown contract this winter, also received a call. The midfielder was the last player taken in the second round of January’s MLS draft, by D.C. United, but was released in preseason and has now signed with Red Bulls' USL team. Despite being passed over by multiple MLS teams, Metzger continues to be summoned by Herzog.

By contrast, left back Mikey Ambrose, a teammate of Metzger’s at Maryland who passed on an FC Dallas homegrown offer and signed with Austin after his junior year, has started four games for Austin and played 90 minutes in each. Born in 1993, he is age-eligible for this Olympic pool but was not invited despite appearing to have better credentials on paper.

Several players have earned callups based on strong MLS showings this winter after being overlooked as collegians. San Jose rookie midfielder Fatai Alashe had never been called into a youth national team camp while at Michigan State. But he had a strong senior year, helping the Spartans to the NCAA quarterfinals and despite missing this winter’s scouting combine with an injury, was selected fourth overall by the Earthquakes and has become a regular in the starting lineup.

Boyd Okwuonu had a stellar career at North Carolina but FC Dallas opted not to offer him a homegrown contract and he was taken 27th overall this winter by Real Salt Lake. A former youth national team star who was dropped after a poor showing at the U-20 team’s World Cup qualifying tournament in 2013 in Mexico, Okwuonu earned a contract with RSL with a strong preseason that has apparently jump-started his youth national team status.

Brooke Tunstall is an American Soccer Now contributing editor and ASN 100 panelist. Follow him on Twitter.