The 25-year-old Harper is the second seed at his home ballpark by virtue of his 22 homers through Tuesday's games. Freeman, the top NL vote-getter for Tuesday night's All-Star Game at Nationals Park, is the seventh seed with 16 homers.
Milwaukee Brewers first baseman Jesus Aguilar faces Philadelphia Phillies slugger Rhys Hoskins in the opening round. Los Angeles Dodgers rookie Max Muncy meets Chicago Cubs infielder Javier Baez, and Houston Astros third baseman Alex Bregman faces Cubs outfielder Kyle Schwarber.
It's the second Home Run Derby for Harper, and the first for the rest of the field. Harper lost to Yoenis Cespedes in the 2013 final at Citi Field in New York.