Clark, 51, is expected to have the opportunity to oversee the player development and scouting departments for the Nationals. He joined the Braves midway through the 1989 season and spent the past 11 years as their scouting director.
The Nationals haven't yet made a formal announcement.
Recognized throughout the baseball world for his ability to recognize amateur talent, Clark will now be reunited with Nationals president Stan Kasten, who left the Braves organization after the conclusion of the 2003 season.
Sources indicated throughout this summer that Clark was angling to join a different organization that would provide him the opportunity to control both the scouting and player development departments.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.