Leonardo Jara (D.C. United)

CLEARWATER BEACH, Fla. — D.C. United’s pursuit of Leonardo Jara to become its starting right back received an instrumental boost from a figure familiar to both parties: United’s Luciano Acosta.

Acosta, Jara said Wednesday, helped persuade him to agree to a deal in which he will join United on a season-long loan from Argentine titan Boca Juniors. Weeks in the making, United formally announced the move Wednesday. Details were not announced, but typically, teams have the option to acquire the player for the long term when the loan expires.

Asked how much Acosta influenced the decision, Jara said through an interpreter: “A lot. I have known him for a while, and to have the opportunity to play with him again motivated me to make the move.”

Jara, 27, joined United over the weekend and has practiced with the team here since Monday. The final paperwork was finalized Tuesday night. He is slated to make his debut in United’s preseason opener Saturday against second-division Bethlehem (Pa.) Steel.

With years of experience playing in Argentina’s first division and South America’s revered Copa Libertadores, Jara will bring an impressive portfolio and the characteristics to fill a glaring void in the lineup. None of last year’s three right backs are available: Nick DeLeon signed with Toronto FC; Oniel Fisher is recovering from major knee surgery; and Chris Odoi-Atsem just completed treatment for Hodgkin’s lymphoma.

With United, Jara will reunite with two teammates from the 2015 squad at Argentine club Estudiantes: Acosta and midfielder Lucas Rodriguez, who also joined United on loan this winter. The trio was together on the field in 11 matches that season.

Aside from their individual talents, Coach Ben Olsen sees a benefit to fielding players who are familiar with one another. “You can tell, he has already fit in,” Olsen said. “It instantly gives you a family within the family.”

Since he and Acosta left Estudiantes, Jara remained closer to Acosta, 24, than with Rodriguez, 21. And in recent weeks, as United’s pursuit of him intensified, Jara turned to Acosta for advice.

“Lucho says living in the United States, you live well, you have a good quality of life compared to Argentina, what we’re used to,” Jara said in his first interview since arriving at training camp. “On the soccer side, he said it’s a good league, it’s good quality.”

Reflecting on the trio’s time together at Estudiantes, Jara said: “It was a good year for us. We all got along and played well together. At the time, Lucas was very young and just starting out. Now he’s a little older and a much better player.”

For United, while Jara is expected to line up on the right side of the back line, Acosta will enter his fourth MLS season as the attacking central midfielder and Rodriguez is likely to start on the left wing (in place of a departed Argentine, Yamil Asad).

“We all know each other well and, at its core, we know the language and each other’s background,” said Jara, who noted he watched Acosta’s MLS matches regularly in Argentina. “Having a friend on the field makes it even easier.”

Although he likes the idea of players from common backgrounds gaining comfort from past experiences together, Olsen wants them to fight for a place on the field.

“The balance is always something you think about within the team, and that includes the cultural balance,” he said. “Not only the soccer part, but making sure they are comfortable and, again, having that family within the family. Everyone also has to stay uncomfortable. We’re here to win games and compete for our jobs.”

Jara said the opportunity to play with Wayne Rooney, United’s English star, also influenced his decision. “He is an unbelievable player, someone everybody in the world wants to play with.”

United will not have to worry about Jara’s fitness. Boca Juniors was active into December, losing to bitter rival River Plate in the Copa Libertadores finals. After the winter break, the club was preparing for the resumption of the domestic campaign.

“For a month, I’ve been in training camp,” he said, laughing, “and now I have to do it again.”

United notes: Fisher, who partially tore three ligaments and meniscus in his right knee late last season, signed a new contract with the club. Terms were not disclosed. His previous deal expired last month. He probably will not be available until the middle of the season.

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