D.C. United was responsible for only a portion of Dwayne De Rosario’s $500,000 salary last year and now inherits his full number. In the wake of his MVP campaign, the player and club are in negotiations to extend and enhance his contract, which expires at the end of this year. (Ned Dishman/GETTY IMAGES)

Bruised by another disappointing MLS season, D.C. United began the winter with a flurry of activity.

It cut ties with its four longest-serving players, trimmed five others, including the second-leading scorer, and acquired a veteran right back. The message was clear: Upgrades were on the way.

And in the subsequent six weeks? Silence.

While most clubs around the league have announced international signings and free agent pickups, United hadn’t introduced anyone until drafting Louisville midfielder Nick DeLeon with the seventh overall pick Thursday.

With players beginning to gather in Washington on Sunday and serious work set to begin next week in Florida, United remains an incomplete project.

Nineteen players are under contract, leaving United to fill at least nine slots before the March 10 season opener against Sporting Kansas City. What’s the holdup?

“Some things take longer than others,” General Manager Dave Kasper said. Both Kasper and Coach Ben Olsen said they have been aggressively pursuing several players and expect to finalize multiple signings in the next few weeks.

The club will also claim three players in the MLS supplemental draft Tuesday and has invited numerous free agents and U.S. lower-league players to training camp.

The coaching staff scouted in Europe, Africa and Latin America. Neither Kasper nor Olsen has publicly identified whom they’re pursuing. The only name to surface was Emiliano Dudar, a well-traveled Argentine center back.

The primary target, however, is a forward, via foreign signing or a trade. A seasoned striker would replace 11-goal scorer Charlie Davies, who was on loan last year from French club Sochaux. United turned down an option to purchase his contract for $1.3 million and decided to not pursue a loan extension. Davies returned to Sochaux this month.

A replacement would alleviate pressure on league MVP Dwayne De Rosario, who had 13 goals and seven assists in 18 appearances after being acquired from New York in mid-season.

Aside from a forward, though, Olsen said he is content with the roster foundation entering his second full season.

“Despite finishing as low as we did last year, there’s a sense of promise,” he said. “We’ve created a good core, and if we add the right pieces to it, we’re going to be a good team.”

Olsen’s core is De Rosario; goalkeeper Bill Hamid, who will miss the start of camp while on U.S. national team duty; right back Robbie Russell, acquired from Real Salt Lake; center backs Dejan Jakovic and Brandon McDonald; defensive midfielder Perry Kitchen; midfielders Chris Pontius, Andy Najar and Branko Boskovic; and forward Josh Wolff.

Pontius, however, is still recovering from a broken leg — a setback that led to United’s late-season slide — and won’t be at full strength until about March 1. Boskovic, the club’s top earner last season at $525,000, has plenty to prove after lacking proper fitness since arriving in mid-2010 and tearing a knee ligament last spring.

“He’s fitter and stronger than he’s ever been with us,” Olsen said. “We were disappointed in him and he has taken it personally. He’s motivated.”

Offseason departures included midfielder Clyde Simms (now with New England) and defender Marc Burch (Seattle). Midfielder Santino Quaranta and defender Devon McTavish retired after being dropped last month. The quartet served 29 seasons combined. Only Pontius and Jakovic have been with United since the start of the 2009 season.

Money will play a role in the acquisitions. Club owner Will Chang doesn’t have the resources of his counterparts at New York and reigning champion Los Angeles, among others, and United isn’t expected to add another big-ticket player.

United was responsible for only a portion of De Rosario’s $500,000 salary last year and now inherits his full number. In the wake of his MVP campaign, the player and club are in negotiations to extend and enhance his contract, which expires at the end of this year.

“I’m excited to get started,” Olsen said. “It’s time to sort it all out and build a team.”