“D.C. United made me the man I am today,” Andy Najar, right, wrote in a letter to the team’s fans after being acquired by Anderlecht of the Belgian league. (Graham Hughes/AP)

Andy Najar entered D.C. United’s youth academy five years ago as a painfully shy immigrant from Honduras with clever feet and boundless promise. The day would come, United officials quickly recognized, when suitors from overseas, flush with cash and tradition, would target the teenager for acquisition.

That time arrived this winter. And as Najar’s offseason loan to Belgian champion Anderlecht was about to expire this week, United agreed to sell the 19-year-old defender-midfielder. The MLS club had rejected at least two offers by Anderlecht in recent weeks before settling on terms Tuesday.

“We said all along the deal had to be in the best interests of both Andy and D.C. United,” General Manager Dave Kasper said after the clubs announced the deal late Wednesday. “Anderlecht stepped up to the plate in the final 48 hours.”

The transfer fee was not disclosed and Kasper declined to discuss details, but according to two people familiar with the negotiations, Anderlecht paid about $3 million. United will receive 75 percent. MLS, which owns all player contracts, will collect the balance.

The deal also includes a “sell-on clause,” meaning United would claim a percentage of a future transfer of Najar by Anderlecht.

He is the first player from MLS’s homegrown initiative to be sold overseas. Homegrown players are typically from the immediate area and rise through a club’s youth system before signing a first-team contract – a standard practice throughout the soccer world. Selling young players to teams in more prominent leagues is also common worldwide.

United has four other homegrowns, including first-choice goalkeeper Bill Hamid, who has drawn interest internationally.

Najar, a 2009 All-Met at Edison High in Alexandria, enrolled in United’s academy program before signing in March 2010. He went on to win MLS’s rookie of the year award. In three seasons, he started 72 league matches and became one of the league’s most exciting young players.

Last summer, he stepped onto a global stage with the Honduran under-23 squad at the Olympics. Najar has also broken into the senior national team and was summoned for a 2014 World Cup qualifier next Wednesday against the United States.

“D.C. United made me the man I am today,” Najar said in an open letter to the team’s fans posted on its Web site. “My teammates have cared for me like a little brother.”

An outside midfielder for 2½ years, Najar was converted into a right back late last season and provided a dangerous dimension to the attack with overlapping runs and stylish footwork. In exhibitions with Anderlecht, Najar has played on the right side of midfield.

“I’m genuinely happy for the kid,” United midfielder Chris Pontius tweeted. “Great player, unreal potential, awesome person.”

Anderlecht, based in Brussels, has won 31 league titles since 1947 and is a regular participant in the UEFA Champions League, European soccer’s most prestigious club competition. American midfielder Sacha Kljestan is in his third season there.

Najar’s departure leaves a considerable hole in United’s roster. Chris Korb, entering his third season, and veteran Robbie Russell are the top candidates to play right back. Korb started on both the left and right side last year and Russell was the first-choice right back until a foot injury sidelined him for two months.

The broader question is whether United will spend a chunk of the transfer fee on a new player. It won’t necessarily purchase a defender. “Andy added a different dimension and it hurt us on the depth chart,” Coach Ben Olsen said, “but we’ve got outside backs we trust and we like.”

United could use the money to address the attacking corps before the March 2 season opener at Houston. The team cut ties over the winter with Branko Boskovic and Hamdi Salihi, and lost Maicon Santos to Chicago in the re-entry draft.

Or United could wait until the summer transfer window, when the market is more plentiful and Olsen has a better grasp of his needs.

“If has to be the right guy,” Olsen said. “If it’s not, we will wait.”