D.C. United didn’t raise ticket prices this winter, but many supporters will have to pay more for admission to RFK Stadium this season.

The Insider has learned that, as part of a preliminary agreement in the lease negotiations between United and stadium officials, a $2 facility fee would be added to the cost of every ticket. Revenue would go toward stadium improvements.

Fans told the Insider that United representatives have been warning them of the planned fee. Season ticket holders who have already paid for tickets would not be affected.

United officials declined to discuss specifics in the negotiations.

“D.C. United is finalizing details of a lease agreement with Events DC,” the organization that operates and manages RFK, club spokesman Doug Hicks said. “At this time, we’re not prepared to discuss points of that partnership but hope to have a final contract in the near future.”

Facility fees are common nationwide for tickets to sporting events and concerts, with $2 on the low end of the scale.

Fans who purchase seats through Ticketmaster will continue to pay a service fee.

Events DC spokeswoman Teri Washington also declined to address the fee issue, saying lease “negotiations are on-going and we are focused on getting a deal done to keep D.C. United here for the foreseeable future.”

United President Kevin Payne said recently: “We’re confident that the District of Columbia and its leadership wants us to remain here and wants to find a way to work with us to accomplish that. We continue to work on parallel charts.”

Ideally, United would like a multiyear deal that would allow it to remain at RFK while continuing to pursue a new stadium project in Washington or Baltimore.

Baltimore and the Maryland Stadium Authority have also looked into the possibility of constructing a facility for United, which has played all 16 seasons in Washington.