Instead of returning to the playoffs for the first time since 2007, midfielder Dwayne DeRosario (pictured) and United (9-12-12) will spend another winter reflecting on shortcomings and searching for ways to take the next step. (Jonathan Newton/The Washington Post)

D.C. United made considerable strides this season, nurturing young players, stabilizing several positions and, in a fleece of a trade, acquiring a game-changing veteran who might end up as MLS’s most valuable player.

United scored more goals, won more games and earned more points than in the ruinous 2010 campaign. As recently as six weeks ago, the club was within striking distance of challenging for first place in MLS’s Eastern Conference.

But a late-season decline exposed the fragile nature of a redevelopment project, and ahead of Saturday night’s finale against Sporting Kansas City at RFK Stadium, United feels as if it missed a wonderful chance to exceed even its own expectations.

Instead of returning to the playoffs for the first time since 2007, United (9-12-12) will spend another winter reflecting on shortcomings and searching for ways to take the next step.

“Missed opportunities,” captain Josh Wolff said. “Just the way we finished out games down the stretch was too much to overcome. Too many points were left out there.”

United’s excruciating draw with the Portland Timbers on Wednesday extended its winless rut to five matches and, for the third time in four years, eliminated the club from playoff contention in the final week of the season.

“We said at the beginning that this is a year to really find out who we are — what young guys we have, what guys we can rely on,” said Ben Olsen, completing his first full season as head coach.

“It’s tough to sit here and talk about that because of the disappointment, but I still think there’s a lot to this team. A couple additions, get healthy next year, and I think we are going to be a tough team to beat.”

Despite the late-season slide, United plans to retain Olsen. Like his young players, the former midfielder showed growing pains. But club officials have preached patience with the rebuilding process and have supported Olsen’s handling of the squad.

“He got every ounce out of this team,” General Manager Dave Kasper said. “He will benefit now having gone through a full year of coaching in this league.”

United was never able to compensate for injuries to midfielder Chris Pontius and defender Dejan Jakovic. Since Pontius (seven goals, five assists) broke his leg Sept. 10, United has a 1-5-2 record. Without Jakovic since late August, the club lost its defensive balance.

Olsen and the front office are going to be busy over the winter. A top priority is reworking the contract of Dwayne De Rosario, 33, who, since his midseason arrival from New York, contributed 13 goals and seven assists in 17 appearances to surge into the MVP discussion.

The club holds an option on the Canadian attacker’s contract for 2012 but would like to extend the pact and enhance his salary. He earned about $500,000 this season.

Then there is forward Charlie Davies and midfielder Branko Boskovic. Despite scoring 11 goals, second best on the team, Davies struggled to replicate the speed and menacing qualities that he exhibited overseas and with the U.S. national team before suffering serious injuries in a 2009 car accident.

United has until Dec. 1 to decide whether to purchase his contract from French club Sochaux for $1.3 million, a fee set last winter when the sides agreed to one-year loan. Kasper declined to comment on United’s plans, but there seems little chance D.C. would spend that much.

United’s other options are to seek to extend the loan, negotiate a considerably smaller transfer price, trade his MLS rights or cut ties altogether.

Boskovic, United’s highest-paid player at $525,000, missed most of the season with a knee injury. His contract runs until the middle of the 2012 season. The club remains high on him and believes he would work well with De Rosario, Pontius and Andy Najar.

The question is whether the 31-year-old Montenegrin wants to return to Europe. If he stays in MLS, he might have to accept a pay cut. United could also reduce his impact on the salary cap through allocation money, which clubs use to offset financial demands. “We saw good things before he did his ACL,” Kasper said. “He’s in our plans moving forward.”

United will also need to address the backline. Jakovic, entering an option year, seems likely to return and partner in the middle with Brandon McDonald. Rookies Ethan White and Chris Korb and veterans Jed Zayner and Daniel Woolard will all probably remain in the mix.

Rookie Perry Kitchen started most of the year at right back in place of the injured Zayner, but his future is in defensive midfield, which might mean the end for seven-year veteran Clyde Simms. Defenders Marc Burch and Devon McTavish, forward Joseph Ngwenya and goalkeeper Steve Cronin are also in jeopardy.

Kasper declined to address specific needs but plans to search for help in the international market, trade circles, re-entry drafts for veterans in December and the college drafts in January.

“I’m very encouraged with a large number of guys and [with] having them come back,” Olsen said. “Some of these young guys have done very well and have now been through an up-and-down season. I hope they learned a lot. I know I have.”