Not sure Atlanta is "small market' anymore. 9th largest metro area in the country, just ahead of Boston.
New York-Northern NJ-Long Island, NY-NJ-PA 18,897,109 New York
Los Angeles-Long Beach-Santa Ana, CA 12,828,837 Los Angeles
Chicago-Joliet-Naperville, IL-IN-WI 9,461,105 Chicago
Dallas-Fort Worth-Arlington, TX 6,371,773 Dallas
Philadelphia-Camden-Wilmington, PA-NJ-DE-MD 5,965,343 Philadelphia
Houston-Sugar Land-Baytown, TX 5,946,800 Houston
Washington-Arlington-Alexandria, DC-VA-MD-WV 5,582,170 Washington
Miami-Fort Lauderdale-Pompano Beach, FL 5,564,635 Miami
Atlanta-Sandy Springs-Marietta, GA 5,268,860 Atlanta
Boston-Cambridge-Quincy, MA-NH 4,552,402 Boston
"Market size", when it comes to sports, doesn't necessarily just mean the population of the metro area. In baseball these days, it mostly means who has the richest owners and spends the most on payroll. In that regard, the Braves are squarely in the bottom half of MLB, and have been since shortly after Ted Turner sold the team over 20 years ago.