Veteran midfielder Brad Davis, far right, will test D.C. United’s struggles on dead-ball situations. (Bob Levey/GETTY IMAGES)

D.C. United has conceded goals in all sorts of manners during this wayward season — a penalty kick, breakaway, counterattacks, headers, an own goal, shots from distance — but recurring breakdowns on set pieces have been most perplexing.

United has allowed corner kicks to skip to open attackers. It has failed to win headers in the box. It has even relinquished a goal off a throw-in.

Of the 13 goals surrendered, seven have come directly or indirectly off a dead ball situation (including a penalty kick).

“If you do that,” Coach Ben Olsen said, “you are going to find yourself in last place.”

Which is exactly where United (1-6-1) resides two months into the season — 13 points behind the Houston Dynamo (5-2-2), the Eastern Conference co-leader and Wednesday night’s foe at RFK Stadium. United has lost three straight at home and five in a row overall as part of the second-poorest start in club history.

Already consumed with remedying a limp attack (four goals in 720 minutes), Olsen also has had to address the set-piece problems.

“Teams have been hungrier than we have been,” he said. “We have been outmanned. It seems like a lot of times they just want it more and they are finding ways to nick balls, get the first [service], maybe a second bite, and when they do that, they start to add up. We just haven’t been good enough.”

Most recently, during a 3-0 loss at Columbus on April 27, United was already trailing by one goal when the Crew’s Josh Williams latched onto a corner kick in front of defender Brandon McDonald. Given United’s scoring rut, a two-goal deficit before halftime severely dented any comeback hopes.

The set-piece issues have plagued several players. The most embarrassing episode came against Philadelphia a week earlier: Sheanon Williams’s long toss was flicked through the box to Jack McInerney on the back side for a routine finish.

“It’s a man-to-man situation,” defensive midfielder Perry Kitchen said. “It’s staying with your guy. Even if you are with your guy, if the ball is two feet away, go win the ball. It’s just a matter of sniffing the ball out and knowing where the danger is.”

Danger is omnipresent on Houston’s set pieces. Veteran midfielder Brad Davis is among the best in the league serving the ball into troublesome spots. In the season opener, Davis’s well-placed corner kick led to an own goal by United’s James Riley in the 80th minute.

“It’s a matter of us wrapping up people, staying with your man and wanting it a bit more than they do,” midfielder Chris Pontius said.

Pontius might return to active duty Wednesday after sitting out one game with a groin injury. However, with a weekend trip to Dallas looming, Olsen seems inclined to hold him back for another few days.

“I have made a lot of progress and I’m happy where I stand,” Pontius said. “Tomorrow is still up in the air but the weekend definitely.”

United is more optimistic about midfielder Nick DeLeon, who has missed more than six weeks with a hamstring ailment. He has yet to regain game fitness but practiced all out for about a week.

“Being on the side has made [the losing] worse because you can’t do anything about it,” he said. “Now that I can hopefully get back into the mix of things, I am excited to bring my energy and hopefully turn this around.”

Off for 10 days, United has the advantage of rest and preparation time. Houston played Sunday night at Los Angeles, defeating the Galaxy in the rematch of the past two MLS Cup finals, and then traveled all day Monday.

However, the Dynamo is 8-1-2 in the past 11 meetings with United, including last year’s two-leg conference finals.

“They have done it before,” Olsen said of Houston’s travel schedule. “They are a very deep team. They know how to get results when they are tired.”