In an agreement reached with the Los Angeles Galaxy weeks ago, defender Omar Gonzalez would not join the U.S. national team until the CONCACAF Gold Cup semifinals next week, the USSF and MLS club confirmed Thursday morning.

CONCACAF announced U.S. roster changes late Wednesday night, presumably taking effect immediately: Gonzalez, Matt Besler, Eddie Johnson and Alan Gordon were added while Oguchi Onyewu, Corey Ashe, Herculez Gomez and Jack McInerney were dropped.

Besler, Johnson and Gordon will join the squad in Baltimore today to begin preparing for Sunday’s quarterfinal against El Salvador at M&T Bank Stadium in Baltimore, but Gonzalez will remain with the Galaxy for Saturday’s home match against the Vancouver Whitecaps and connect with the Americans in Dallas for the semis — should they defeat the Salvadorans.

No such compromises were reached on MLS players Besler, Johnson and Gordon.

Clubs are required to release players for FIFA-sanctioned championships, but in the spirit of goodwill and maintaining long-term relationships with club coaches, national teams are often flexible in their call-ups and timetables. For example, U.S. Coach Juergen Klinsmann did not request his European-based regulars for the Gold Cup because, after weeks of American duty for World Cup qualifiers last month, they needed a break ahead of club training camps.

Besler might have remained with Sporting Kansas City through the weekend had Onyewu not suffered an ankle sprain.

Ashe suffered a thigh injury and did not play in the group stage of the Gold Cup. Gomez made two appearances but was still feeling the effects of a knee injury that has bothered him for about six weeks. In addition, his new club, Tijuana, opens the Mexican season Friday night. McInerney, 20, did not play in the group matches and and was, in essence, invited for a maiden experience on the senior level.

Who will start in central defense Sunday? Michael Orozco Fiscal seems certain to maintain his slot after starting each of the three group matches. Clarence Goodson made two starts, sandwiched around Onyewu’s appearance. Besler, though, has risen to the top of Klinsmann’s depth chart this year. The question is whether he could step back into the lineup without much time training with the current group.

Following Tuesday’s victory over Costa Rica in the group finale, Klinsmann gave the players two days’ off. They will resume workouts Friday morning afternoon at an area college and train at the downtown stadium Saturday afternoon. Training sessions are closed to the public.

Ticket sales for the Sunday doubleheader — Costa Rica will face Honduras in the other game — have reached 52,000, organizers said this morning. Capacity is 69,000.