Andrew Boyens and Dwayne De Rosario vie for a high ball. (Victor Decolongon/Getty Images)

It’s just two games into the MLS season, and D.C. United is showing signs of trouble.

With two high-priced players dropped from the starting lineup and two others on U.S. national team duty, United was outclassed from the beginning Sunday and dropped a 3-1 decision to the Los Angeles Galaxy at Home Depot Center.

Hamdi Salihi, the proven European scorer that United had coveted over the winter, remained on the bench throughout the blustery day, even though the club trailed throughout the second half. Meantime, central midfielder Branko Boskovic wasn’t summoned until the 61st minute.

On the surface, the absence of the big-ticket players was glaring.

“I don’t care what it looks like on the surface,” Coach Ben Olsen said.

Maicon Santos, a well-traveled forward, beat out Salihi for the starting role, Olsen said. He had planned to insert the Albanian in the second half, he added, but a groin injury to defender Dejan Jakovic altered the plans.

Said Salihi: “He told me before that he had something else in mind with Maicon in front. I accept everything, the decisions from him.”

Likewise, Boskovic accepted the change, citing his lack of fitness after returning from major knee surgery last year.

United was already without goalkeeper Bill Hamid and midfielder Perry Kitchen. They are with the U.S. under-23 squad pursuing an Olympic berth. Joe Willis, Hamid’s replacement, made several superb saves, but for the second consecutive match, United’s best player was its goalie — not a good sign.

Willis’s work and the Galaxy’s faulty finishing prevented an early pummeling.

“I’m disappointed in the group because they are a reflection of me and this organization,” Olsen said. “At the minimum, the fight has to be there. We gave them too much respect early and we didn’t [appreciate] that this was going to be one hell of a tough game.

Shouldn’t United (0-2) have been more focused on playing the defending MLS champions?

“You would think,” Olsen said. “It’s not going to happen again because I’m not going to put guys out there where that’s going to be a trend. It’s pretty simple.”

Irish World Cup striker Robbie Keane scored twice for the Galaxy (1-1), which was playing its fourth match in 12 days (two in MLS, two in the CONCACAF Champions League). Reserve Marcelo Sarvas stretched the lead in the 86th minute before United rookie Nick DeLeon answered in the 87th.

“We didn’t come ready to play,” defender Robbie Russell said. “We knew we had an opportunity because they had played a lot of games and we had a chance to put some pressure on them. We started very slowly.”

The Galaxy, unbeaten in eight straight against United, showed no signs of fatigue. United’s Andy Najar was fortunate not to be called for a handball in the box on a sequence that ended with David Beckham whistling a 25-yarder over the crossbar.

Mike Magee missed an eight-yard one-timer, and after Magee beat Russell for an angled run at goal, Willis made a foot save. Beckham’s free kick swerved fractionally wide left and Willis raced out to block Keane’s effort.

United almost reached halftime without suffering any damage. But in the 45th minute, Magee located Todd Dunivant on the left side of the penalty area. Dunivant headed to Keane floating behind Jakovic at the back post for a simple finish. United center back Brandon McDonald stomped his feet in disgust.

Emiliano Dudar entered for Jakovic after the break and should’ve tied it in the 56th minute, but after chesting the ball down, missed high from a mere five yards.

United squandered another opportunity in the 66th when Maicon Santos’s miss wasted a nice build-up by Dwayne De Rosario, Najar and Chris Pontius.

With that, United faded away. Landon Donovan stripped a United player and dashed into space before supplying Keane with a diagonal ball. Keane fired a 14-yarder into the far upper corner in the 69th minute.

Later, Beckham crossed to Sarvas for a nine-yard header. DeLeon answered by curling in a 12-yarder.

“I’m concerned at 0-2,” Olsen said. “No one wants to be 0-2 and deal with this, but we’re moving forward and we’ll get things sorted out.”

United notes: The club will practice in the Los Angeles area for several days before traveling to Vancouver ahead of Saturday’s match against the Whitecaps at BC Place. . . . Najar will join the Honduran squad for Olympic qualifying and miss at least one MLS game.