Oniel Fisher, left, tracks Montreal’s Ignacio Piatti during an Aug. 4 match. (Jean-Yves Ahern/USA Today Sports)

D.C. United is in MLS playoff contention because Wayne Rooney arrived and Luciano Acosta revved his little engines, because Bill Hamid returned from Europe and Russell Canouse returned from long-term injury. It’s happening because the collective effort has taken hold and confidence is rising after four wobbly months.

United is also in the tight Eastern Conference race for the last few postseason slots because of a quick Jamaican defender with an unusually high uniform number who, in his first year in Washington, has taken to the starting job at right back.

Acquired in a minor preseason trade, Oniel Fisher figured to be a substitute and occasional starter. But with injuries to both incumbents on the back line’s corners, Fisher has played an integral part in United’s summer resurgence.

On Sunday night, when D.C. visits the New York Red Bulls for the second meeting in the thrice-annual rumble, Fisher is likely to make his 15th consecutive start and 17th overall — one short of his career total in three seasons with the Seattle Sounders.

“He’s growing into that role more and more,” Coach Ben Olsen said. “Oniel has done a tremendous job for us.”

Fisher, 26, has been at his best joining the attack with overlapping runs and confident bursts. On Aug. 15, he pushed forward early in the second half and scored the go-ahead goal in a 4-1 comeback victory over the Portland Timbers at Audi Field.

Although it was his first goal since 2014, when he was a senior at the University of New Mexico, Fisher reacted as if it were commonplace.

Afterward, United’s other Jamaicans, reserve forwards Darren Mattocks and Dane Kelly, needled him about the understated celebration.

“Aw, you didn’t even know what to do!” one said.

He responded: “I don’t need to celebrate. That was my celebration — just to relax and enjoy it.”

Four days later, Fisher did not score in the 2-0 victory over visiting New England. But his first-half forays added another dangerous element in what was United’s most artistic and attractive half of the season. Fisher combined with winger Paul Arriola to put the Revolution under pressure, beat players on the dribble and crossed effectively.

The guy who wears No. 91 (his birth year) was among United’s best performers.

“I know he likes that part,” Olsen said. “As long as he continues to understand his [defensive] role back there, it’s great he can support the attack and get forward.”

To reach this point in his career, Fisher has had to go considerable distances: Portmore, Jamaica, where he played for Saint Catherine parish teams with Kelly; Tyler, Tex., for two seasons in junior college; Albuquerque for two years with New Mexico’s Lobos; and Seattle, which claimed him in the second round of the 2015 MLS draft.

He spent much of his time with Seattle’s second-division squad, and when he was with the first team, he was out of position on the left side.

This preseason, Fisher expressed interest in going elsewhere if he wasn’t going to be in the Sounders’ plans. Seattle obliged, shipping him to D.C. for $50,000 in general allocation money. He arrived two weeks into training camp in Florida.

With Taylor Kemp sidelined indefinitely with hip and groin injuries, Fisher started at left back in the first two matches. Joseph Mora, a Costa Rican newcomer, took over in the third game, leaving Fisher on the bench for three matches and as a second-half sub for three more.

He then got his chance on his favored right side, and a few weeks later, when first choice Nick DeLeon went down with a knee injury, it was Fisher’s job for good. DeLeon remains sidelined, and United did not acquire any depth at that position before the Aug. 8 transfer and trade deadline closed.

“I feel more comfortable knowing this is my best position,” said Fisher, who is in the last year of his MLS contract. “I need to do well every time I step onto the field.”

Although few other options at right back exist, Olsen has not ruled out adjustments for the heavy schedule down the stretch, saying, “We might have to get creative at some point over there.”

For now, the freedom to attack has boosted Fisher’s confidence — and the team’s confidence in him.

United has “given me the green light to go whenever I can,” he said. “I trust them to give me the ball and cover for me, but I’ve got to do the right things, too.”

***

D.C. United at New York Red Bulls

Where: Red Bull Arena in Harrison, N.J.

When: Sunday, 7 p.m.

TV: Fox Sports 1

Records: United 7-9-6, 27 points; Red Bulls 15-6-4, 49 points

D.C. probable starters: GK Bill Hamid; Ds Oniel Fisher, Kofi Opare, Steve Birnbaum, Joseph Mora; MFs Paul Arriola, Junior Moreno, Russell Canouse, Luciano Acosta, Yamil Asad; F Wayne Rooney

N.Y. probable starters: GK Luis Robles; Ds Michael Murillo, Tim Parker, Aaron Long, Kemar Lawrence; MFs Marc Rzatkowski, Tyler Adams, Sean Davis, Kaku, Danny Royer; F Bradley Wright-Phillips

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