As his career began to blossom and his curiosity broadened, Facundo Erpen figured he would soon be leaving his native Argentina for a new opportunity in the vast soccer universe.

His older brother, Horacio, had gone to a low-level club in Italy and his twin brother, Andres, was making plans to play in Uruguay. Facundo, a 22-year-old defender who had enjoyed a spell in the famed Boca Juniors development program before starring with Talleres of Cordoba, thought his destination would be Colombia.

Then he got word early this year that an ambitious club in the young American league, MLS champion D.C. United, was interested.

"I was very happy that I had been noticed by a team outside of Argentina," he said through an interpreter yesterday. "Now that I'm here, I am glad I made the decision."

A half-year courtship concluded last week when Erpen signed a multiyear contract with MLS and joined United for the final two months of the regular season. Financial terms were not disclosed, but it's believed MLS paid $200,000 to acquire his rights and United provided a salary of about $75,000.

Erpen received his international clearance Thursday and is eligible to play tonight when surging United faces the fading Los Angeles Galaxy at RFK Stadium. However, because Erpen hasn't played in a real game since the conclusion of the Argentine second-division season two months ago and is still adjusting to new teammates, his debut might be delayed until next week.

"He was pretty good in the last couple of days in training," Coach Peter Nowak said. "You can see when we started to work with him his lack of fitness and the lack of games, but he's getting better. We'll see what happens during the game and what we need."

Erpen's arrival comes at an awkward time. United's defense has registered shutouts in the last two games to lower its goals against average to a league-best 1.05. Rookie Bobby Boswell and veterans Bryan Namoff and Brandon Prideaux have formed a solid back line, with left back John Wilson in reserve.

So where does that leave Erpen? With a busy schedule over the next six weeks, United believes it needs the defensive depth to make a serious postseason run. Erpen said he is comfortable both in the middle and on the right in a three-man alignment.

"We're not going to hand him anything; he will have to earn it," Nowak said. "He will have a chance to show what he's capable of and what he can contribute."

Said Erpen: "I can be a good organizer in the back, someone who can be vocal and let everyone know where they need to be. This is a team that has very good midfielders who are good with the ball at their feet and good forwards who know what to do with the ball. I can bring that stability in the back and the support that the rest of the team needs."

Erpen -- whose father is a former player and now a youth coach with Argentine fourth-division club Juventud Unida -- also brings communication skills. His mother is an English instructor at a language institute near the family's home in Gualeguaychu north of Buenos Aires, and although Erpen is more comfortable doing media interviews in Spanish, he is able to converse in English. The transition has been eased by an Argentine compatriot, second-year midfielder Christian Gomez, and several bilingual teammates and staff members.

His MLS education began last week when he watched United's impressive victories over the MetroStars and Chivas USA.

"It's a very good level," he said. "It's a fast-paced league, very similar to the English game. In Argentina, it's a little more possession and players taking on players. It's going to take me a little bit of time to get adjusted to that rhythm, but I hope to be on the field and contributing soon."

United Notes: Forward Jaime Moreno and goalkeeper Nick Rimando were named to the 19-man MLS select squad that will face world power Real Madrid in Spain on Tuesday. They are expected to return in time for the U.S. Open Cup quarterfinal vs. Dallas the next day, but whether they'll play is uncertain. Dallas midfielder Ronnie O'Brien will have the same predicament. The Galaxy's lone representative is forward Landon Donovan. . . . D.C. midfielder Ben Olsen (strained oblique muscle) is doubtful tonight. Forward Freddy Adu (sprained knee ligament) has been upgraded to questionable but probably won't play until Wednesday. Forward Alecko Eskandarian (concussion) and defender David Stokes (ankle) remain sidelined.

Defender Facundo Erpen, front, "will have a chance to show what he's capable of," United Coach Peter Nowak said.