Major League Soccer will continue to expand over the next several years, with new clubs already planned for New York, Miami, and Orlando. According Jonathan Tannenwald of Philly.com, that expansion will find another southeastern home in the city of Atlanta.
At present, Atlanta is home to the Silverbacks of the NASL. There is no word in this report whether or not MLS would be targeting the SIlverbacks, or whether they'd be looking to create an entirely new club from the ground up. There are suggestions that Atlanta Falcons' owner Arthur Blank is involved, and at present, he isn't involved with the North American Soccer League side in any way. Because of that, I'd be surprised to see Don Garber attempt to lure the Silverbacks into MLS.
Atlanta has been working toward a new football stadium for some time, and potential MLS expansion has often been tied to that project. The rumored involvement of Blank would seem to be another hint that the expansion side will, indeed, be sharing their home.
The Cosmos have enjoyed both of their trips to Atlanta since rejoining the league last fall. They won the regular season finale 1-0, before winning the 2013 Soccer Bowl by the same score just one week later. The Silverbacks will kick off the 2014 spring season in New York, seven days from now.