The Washington-based outfit are looking at the option at moving about 40 miles, with Maryland Stadium in mind to be their potential new home.
DC president Kevin Payne confirmed that plans were in place for a possible relocation.
"Our name is D.C. United, but we're not playing [tactical] games here," Payne told the Washington Post's Insider. "Baltimore has dealt with us in good faith and it's a very good opportunity. It's a good location. The developer has also dealt with us in very good faith.
"We believe Baltimore can get something done. It's a real opportunity."