DC United soccer Managing Partner Jason Levien, seated left, and Washington Mayor Vincent Gray, seated right, sign a public-private partnership to build a soccer stadium during a news conference in Washington, Thursday, July 25, 2013. DC United and city officials have agreed to a deal that would keep the Major League Soccer franchise in the District of Columbia with a new, $300 million soccer-only stadium. (AP Photo/Kevin Wolf )

Photo by: Kevin Wolf

DC United soccer Managing Partner Jason Levien, seated left, and Washington Mayor Vincent Gray, seated right, sign a public-private partnership to build a soccer stadium during a news conference in Washington, Thursday, July 25, 2013. DC United and city officials have agreed to a deal that would keep the Major League Soccer franchise in the District of Columbia with a new, $300 million soccer-only stadium. (AP Photo/Kevin Wolf )