PORTLAND, Ore. -- Midfielders Freddy Adu and Amobi Okugo got word Monday that they will head to Nashville following tonight's season opener with the Union, having received call-ups to the United States U-23's final training camp in advance of its Olympic qualifying tournament.

Per MLS policy, players are not available for comment prior to matches, so I'll try to snag comments from either Adu or Okugo (or both) afterward.

The U.S. club will compete in Group A in the CONCACAF Olympic Qualifying tournament, which kicks off March 22 at LP Field in Nashville. Adu and Okugo could miss three matches with the Union, should the U.S. side require their services for that long. Those matches are: March 18 vs. Colorado; March 24 at Chicago and March 31 vs. Vancouver.

Here's a look at the rest of the roster:

GOALKEEPERS (2): Bill Hamid (D.C. United; Annandale, Va.), Sean Johnson (Chicago Fire; Lilburn, Ga.)

DEFENDERS (6): Josh Gatt (Molde; Plymouth, Mich.), Perry Kitchen (D.C. United; Indianapolis, Ind.), Ike Opara (San Jose Earthquakes; Durham, N.C.), Kofi Sarkodie (Houston Dynamo; Huber Heights, Ohio), Zarek Valentin (Montreal Impact; Lancaster, Pa.), Jorge Villafaña (Chivas USA; Anaheim, Calif.)

MIDFIELDERS (6): Freddy Adu (Union; Potomac, Md.), Joe Corona (Club Tijuana; Chula Vista, Calif.), Mix Diskerud (Gent; Oslo, Norway), Jared Jeffrey (Mainz; Richardson, Texas), Amobi Okugo (Union; Sacramento, Calif.), Michael Stephens (LA Galaxy; Naperville, Ill.)

FORWARDS (5): Juan Agudelo (New York Red Bulls; Barnegat, N.J.), Terrence Boyd (Borussia Dortmund; Berlin, Germany), Teal Bunbury (Sporting Kansas City; Prior Lake, Minn.), Joe Gyau (Hoffenheim; Silver Spring, Md.), Brek Shea (FC Dallas; Bryan, Texas)