Maryland’s Patrick Mullins is one of several players D.C. United could select with the first overall pick in the MLS draft on Thursday. (Rich Schultz/Associated Press)

D.C. United officials arrived at a downtown hotel here late Wednesday afternoon with arms full of luggage and a secret: their choice with the No. 1 pick in the MLS draft at noon Thursday.

Without a consensus top candidate, United could go in one of four directions:

●Maryland forward Patrick Mullins, the NCAA’s leading scorer who last week won his second consecutive Hermann Trophy as the nation’s best player.

●California’s Steve Birnbaum, the most game-ready player from a deep pool of central defenders.

●California’s Christian Dean, Birnbaum’s central partner who left school a year early and might have the greatest potential in the draft class.

●Or a trade.

“We have narrowed it down to a very short list,” said General Manager Dave Kasper, whose club finished with the fewest victories in MLS history last season (3-24-7).

He declined to comment about specific players, but Mullins, Birnbaum and Dean are widely considered their best options. Connecticut’s Andre Blake is also high on the league-wide list, but United is not in the market for a goalkeeper.

Kasper said the recent MLS combine in Fort Lauderdale, Fla., did not prompt the team to reassess its draft approach.

As for dealing the pick, “There has been interest. It’s not out of the realm of possibility.”

However, without a can’t-miss prospect in the mix, there does not seem to be an insatiable hunger to move into the top slot.

Assuming it does not trade the pick, United will use the draft to further strengthen a position — back line or front line — that has already undergone offseason transformation. Through trades and signings, United acquired three experienced defenders (center backs Bobby Boswell and Jeff Parke and right back Sean Franklin) and two proven goal scorers (Eddie Johnson and Fabian Espindola).

Mullins scored 19 goals last season in leading the Terrapins to the College Cup final. The 6-foot-2 Birnbaum sat out the 2012 season with a knee injury but returned to earn first-team all-American honors last fall. The 6-foot-3 Dean thrives in the middle but also can play on the left side — a position where United lacks depth.

United is going to need depth in a campaign that also will include the CONCACAF Champions League and the annual U.S. Open Cup. Despite a woeful regular season record, United qualified for the international tournament by winning the Open Cup in October.

United is picking first overall for the fourth time in MLS’s 19 seasons. Previous selections were Virginia midfielder Jason Moore (1999), Virginia forward Alecko Eskandarian (2003) and 14-year-old Freddy Adu (2004).

Other players forecast for early selection Thursday: Maryland forward Schillo Tshuma, an Episcopal School graduate and The Post’s fall 2011 All-Met player of the year who left College Park two years early; and Georgetown senior forward Steve Neumann.

United does not have a second-round pick Thursday but holds selections in each of the last two rounds Tuesday.

United notes: Kasper said the club is “committed” to signing Johnson to a contract that would make him a designated player (a salary in excess of $387,000). His current deal is valued at about $175,000, which had prompted him to seek a trade from Seattle.

Talks will commence when he returns from U.S. national team duty. . . .

United is close to reaching a deal with Espindola, who posted 28 goals and 12 assists the past three seasons with Real Salt Lake and New York. The club claimed his rights in the re-entry draft last month. . . .

The club is also close to hiring an assistant coach to replace Josh Wolff, who moved to the Columbus Crew. Italian-Canadian Enzo Concina, 51, who worked for Napoli and then Inter Milan, is the top candidate.

Meanwhile, United’s Michael Seaton, a 17-year-old homegrown forward from Capitol Heights, is training with Inter Milan’s academy squad. He will return in time for the start of training camp Jan. 25 in Washington. Indonesian businessman Erick Thohir is the primary benefactor for both United and Inter.