Substitute forward Jairo Arrieta eyes the ball against Ronald Zubar and the Red Bulls on Sunday in MLS playoffs. (By Tony Quinn)

From the middle of May until late August, D.C. United stood atop the Eastern Conference – the longest stretch any of the 20 MLS clubs spent in first place this season.

United was a good team, a playoff team, yet belying the bountiful summer, it was not a great team. Ben Olsen’s bunch was getting by with chemistry, experience and resilience – qualities that, amid league parity and the regular season grind, went a long way.

While the accumulating point total suggested an MLS Cup contender, the team’s makeup said otherwise.

By late in the campaign, Olsen had squeezed everything he could out of a low-budget roster, mixing and matching players and making economic changes in a time of big-ticket signings elsewhere around the league.

United was not a stylish or high-scoring team – some fans considered it downright boring – but it worked.

Again and again, though, Olsen warned that United walked a thin line: If a few players had not performed at full capacity, if the hunger dropped off for a night, if injuries struck at the same time, if everything didn’t go just right, those harrowing victories would not have been possible.

So it should not have come as any surprise that, despite a mostly profitable regular season, United was on borrowed time in the playoffs. It had stumbled into postseason in a two-month rut and, after another stirring comeback against New England in the first round, D.C. lost to New York in the two-leg conference semifinals without scoring a goal.

[United’s attack comes up empty, and its season comes to a close]

While disappointment saturated the visitors’ locker room at Red Bull Arena on Sunday, there was a prevailing sense among players and technical staff that this stage was as far as the unit could have realistically gone.

Sure, United was capable of defeating its arch rivals — the aggregate score, after all, was only 2-0 – but the difference between the teams was clear.

And as the offseason approaches, United supporters are left to wonder whether next year will offer anything different. What United has done the past two campaigns wasn’t so bad: winning records and appearances in the conference semifinals. Taking the next step, though, will require roster upgrades.

And therein lies the problem. United says it loses a ton of money playing at RFK Stadium, its city-run home for 20 years. Until the proposed arena opens at Buzzard Point, probably in 2018, the club will continue missing out on the financial nourishment that most other MLS clubs harvest from new stadiums.

Ben Olsen, after the season-ending defeat at Red Bull Arena on Sunday. (By Tony Quinn)

With more cash going out than in, ownership has kept a tight budget in recent years. Olsen and General Manager Dave Kasper have had to make do. And to their credit, since a disastrous 2013 campaign, they’ve fielded a winning team by acquiring castoffs, drafting well and making wise trades. Around the league, both are well respected for their work with limited means.

MLS’s salary cap helps maintain a competitive balance, but as the league continues loosening the constraints and allowing exceptions for marquee signings, United is in danger of falling behind.

Success is possible without writing large paychecks. Despite having the lowest payrolls, FC Dallas and the Red Bulls finished first in their respective conferences. Both have also advanced to the conference finals. (United was third from the bottom in salaries.)

United’s most glaring need, though, will probably require a big contract: a central midfielder who can possess, pass and alter a match by running into the heart of a defense. In the last 19 matches, including playoffs, United enjoyed the majority of possession only four times. On Sunday, United’s most dangerous distribution came from goalkeeper Bill Hamid’s long kicks and tosses.

Without a true ringleader, United will remain opportunity-seekers rather than creators.

From early indications, most of the current squad will return next year and any impactful changes might have to come through thrifty avenues.

Before the season even ended, United announced new contracts for defenders Bobby Boswell and Kofi Opare and forward Chris Rolfe. Sources say the club has also come to terms with midfielder Nick DeLeon and forward Alvaro Saborio, a midseason acquisition from Real Salt Lake. Several others are under contract next year.

The status of two longtime regulars is unclear: Defensive midfielder Perry Kitchen’s deal expires next month and attacker Chris Pontius’s hefty pact is entering an option year.

One source said negotiations with Kitchen are not going well – he is apparently seeking a large bump on his current $260,000 salary — and that he might end up signing overseas.

Kitchen, 23, has started 155 of 170 regular season matches since leaving the University of Akron after one year. Although Kitchen did not make huge strides this year, his departure would leave a glaring void.

The club would love to keep the oft-injured Pontius but not at his $400,000 rate. In order to stay in Washington, he would probably have to agree to a pay cut.

Finnish national team midfielder Markus Halsti, the club’s primary acquisition last winter, was slowed by injuries and didn’t secure a starting job until Davy Arnaud suffered a late-season concussion. Halsti is under contract in 2016, so unless the sides agree to part ways, he will return.

If Kitchen leaves, Halsti would become a candidate to play defensive midfield. That would, in turn, force the club to address the other central position.

Questions also swirl around Arnaud, whose energy and leadership were sorely missed down the stretch. At 35, he might decide health and family outweigh trying to return from a head injury that has sidelined him for months. United will also have to consider the age of its roster: eight players are 30 or older.

Beyond MLS, United will also have to take into account the CONCACAF Champions League: For the second straight year, the club is in the quarterfinals. Without a roster boost, though, United stands little chance against a Mexican foe before the MLS season begins.

What we do know about United in 2016 is that it will continue embodying Olsen’s grit and passion. It will find ways to win at home and endure on the road.

And in all likelihood, until that new stadium begins rising off South Capitol Street, it will have to continue making the most of what ownership allows.