Maybe not quite yet but if you read between the lines then a move may be imminent.
According to the Washington Post article, Major League Soccer is attempting to gauge fan interest about a team in Baltimore. While the article does state through either expansion or relocation, when you read between the lines it is pretty clear they are taking about DC United.The survey at the end lists teams with soccer specific stadiums, 3 of which had their stadiums just built in the last 2 years. DC United is pretty much the only viable relocation candidate.
Now there remains the possiblity that this whole thing may be a ploy on Major League Soccer's behalf to get negotiations rolling on a new stadium for the United. After all, you don't have to be a DC resident to know that RFK is not a suitable home for them and that they have been trying unsuccessfully for years to get a soccer specific stadium.
If that is the case then this would be reminiscent of the New England Patriots' proposed move to Hartford a few years ago before Gillette Stadium was built.
Since the low point for the league when they had to fold the Florida franchises a decade ago, the league has achieved a lot of growth. It is more popular than ever, the level of play is the best it has ever been despite multiple expansions, and the new franchises have generated tremendous fan interest in their regions.
However, allowing DC United, the league's most storied franchise (in its short history), to leave the DC area would be a tremendous mistake.