Monumental Sports chief executive Ted Leonsis, who owns the Wizards and the Capitals, has long been a booster of sports gambling in the District. (Photo by Finlay Mackay for The Washington Post; photo illustration by Gene Bresler/Catchlight)

Events D.C., the District’s official convention and sports authority, has approved a 35,000-square-foot retail and entertainment space and potential sportsbook at Nationals Park, as the city prepares for legalized sports betting.

Gregory O’Dell, the president and chief executive of Events D.C., said the retail space on First Street SE was originally envisioned as a sports lounge but could be converted to a sportsbook.

The Nationals have not revealed their plans for the area and declined to comment for this article.

The District’s contribution for the space, authorized by the Events D.C. board, is $3.6 million, while the baseball team is expected to spend as much as $60 million to build it out. The area is set to open in 2020, according to Events D.C.

D.C. elected officials legalized sports betting last year, paving the way for sportsbooks at arenas, betting machines in restaurants and a city-owned betting app for smartphones.

The law specifically allows for brick-and-mortar establishments for wagering at Capital One Arena in Chinatown, Nationals Park in Navy Yard, the newly constructed Audi Field and the St. Elizabeths East Entertainment and Sports Arena in Congress Heights. The city charges $250,000 for a five-year license for sports-gambling sites at arenas.

Monumental Sports chief executive Ted Leonsis, whose company operates Capital One Arena, has been one of the most enthusiastic boosters of sports betting and has said there will be a sportsbook at the arena, which hosts the Wizards and the Capitals. Since Monumental Sports bought out the site that formerly housed the Green Turtle sports bar, there has been speculation that at least part of the space could be used for a sportsbook.

Events D.C. operates the St. Elizabeths arena in Southeast Washington — the home court of the WNBA’s Washington Mystics and the Capital City Go-Go, an NBA G League team — but has no immediate plans for a sportsbook on-site.

“We have to get the development around us to mature, and that neighborhood to mature,” O’Dell said.

A D.C. United spokesman said team owners were still weighing options for an Audi Field sportsbook and had no updates.

District officials have said they would like to launch sports betting by the fall.

The D.C. Council authorized the city to issue a sole-source contract to Intralot, the lottery manager, to oversee the sports-betting mobile app and related online services.

City officials are discussing the terms of the contract with the goal of finalizing negotiations by summer, according to a spokesman for the Office of the Chief Financial Officer, which is overseeing the sports-betting program.

Scott Allen and Jesse Dougherty contributed to this report.