With four days remaining before the Washington Redskins’ home opener against the Indianapolis Colts, thousands of tickets remain unsold at FedEx Field. The unsold seats, combined with the Redskins’ admission that they no longer have a season ticket waitlist, raises a previously unthinkable question: Will Washington’s home opener sell out?

Redskins officials would not say how many seats were available at FedEx Field, which has been scaled back at least three times in recent years, from 91,704 to 82,000 seats, according to the team’s figures. But a review of available, previously unsold tickets on NFL Ticket Exchange showed that more than 3,650 were available Tuesday morning in all sections of the stadium, across all price points, for Sunday’s game.

The Redskins have long maintained that every game is sold out and boasted in this year’s media guide that the run of sellouts dates back 50 years. The attendance streak has been a source of enormous pride for the franchise, one of the oldest in the NFL whose storied tradition includes five appearances in the Super Bowl and three Super Bowl titles. The last of those championships was in 1992, and over the past quarter-century the Redskins’ fortunes on the field have declined.

Fan enthusiasm has diminished in recent years, a circumstance the team tacitly acknowledged in June when it announced without explanation that a season ticket waiting list it once said numbered 200,000 no longer existed. The availability of tickets for this Sunday’s game is another sign of flagging fan interest.

The Redskins’ 2018 media guide states that the team’s sellout streak — which it said began in the 1960s when the team played at RFK Stadium — continued through last season. “FedEx Field increased the Redskins’ attendance capacity by more than 40 percent when the team left RFK Stadium after 1996,” the media guide says. “Nevertheless, the Redskins have sold out every home game for the past 50 seasons. All 210 (preseason, regular and postseason) contests at FedEx Field through the 2017 season have been sellouts.”

Redskins officials acknowledged Tuesday that tickets remained for Sunday’s home opener, as well as the possibility that the home-game sellout streak dating back to 1967, which they insisted is legitimate, will likely end this weekend.

Sellouts or not, in recent years thousands of seats are often unfilled at many home games.

The June announcement of the end of the waiting list was followed by an aggressive advertising campaign appealing to potential ticket buyers — the first such effort in recent memory.

That campaign continued an hour after Washington’s first victory of the season. “REDSKINS WIN! Next up: Colts,” read a Sunday night email from the team, announcing “single game tickets available now.” Such an announcement, a week before the home opener, would have been unthinkable for most of the last half-century.

Similarly jarring were the promotional reads during the team’s preseason play-by-play broadcasts, hawking ticket packages. “Season tickets available to the public for the first time in years!” announced Kenny Albert during one such game.

The team’s website, meanwhile, continues to advertise both single-game and season tickets. “Buy season tickets & save big money on our biggest games,” read one ad, accompanied by a chart touting the savings of season ticket packages.

The Redskins are also posting ads on social media that have placed special emphasis on Sunday’s home opener. The team also designated the Colts game as “Maryland State Employee Appreciation Day” and added as a perk a chance for each state employee who buys a lower-level ticket to have his or her picture taken on FedEx Field after the game.

The team has not said publicly the reasons behind the change of tactics on ticket sales, but the new transparency about demand was accompanied by the arrival this spring of Brian Lafemina as its new president of business operations. Lafemina’s previous work in the NFL has included helping other franchises with stadium operations, including overhauling and improving their ticket-selling operations.

Under Lafemina’s guidance, the team this summer also announced a number of steps it was taking to make its often-criticized home in Landover a more attractive destination for fans. These include a new fan pavilion on the lower concourse, discounts on food for season ticket holders, new menu items and an expanded craft beer list.

“We want to encourage Redskins fans to come to games, grab the home-field advantage back and fill the stadium with burgundy and gold,” Jake Bye, the new senior vice president of consumer sales and marketing, told reporters in July. Bye spent the past 12 seasons with the Rams, who moved from St. Louis to Los Angeles before the 2016 season.

The level of fan enthusiasm this season certainly can’t be hurt by the Redskins’ 24-6 victory over the Arizona Cardinals on Sunday, their first win on opening day in Jay Gruden’s five years as head coach. But the process of rebuilding a fan base that once seemed impossible to alienate will take longer than a single game.

For many fans, the game-day trek to FedEx Field, which ranks near the bottom of fan surveys of the best-and-worst NFL venues, is another disincentive to a $567.50 outing. That’s the average cost for two people to attend a Redskins game at FedEx, according to GoBankingRates.com, covering tickets, parking and a hot dog, beer and soda apiece. It ranks ninth most expensive in the NFL.

The erosion of fan support is no minor, temporary concern for the Redskins and their owner, Daniel M. Snyder. The Redskins are embarking on plans to build their next stadium when their lease for the land occupied by FedEx Field in Prince George’s County expires in 2027 — and filling that new stadium will be a priority.

While nine years may seem the distant future, it’s not in the timetable of erecting a state-of-the-art NFL stadium. Ideally, the site would be selected as much as a decade in advance to lay the groundwork for essential infrastructure and transportation needs.

The Redskins have yet to announce whether they will build in northern Virginia, Maryland or the District’s RFK site, where they played from 1961 to 1996. According to a person with knowledge of the process, team officials are awaiting proposals from each jurisdiction.

Earlier this month, Washington Mayor Muriel E. Bowser left no doubt about her wish that the Redskins return to the RFK site in Northeast, declaring “Bring ’Em Home” in remarks at the Redskins’ annual Welcome Home luncheon. Looking on with approval was Snyder, her seatmate at the event’s head table, who declared her speech “great.”

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