Singer and Rizzo worked together for three years when both were with the D-backs. Singer joined the Nationals in 2009 and became special assignment scout and Washington's coordinator of Pacific Rim operations. Outside of Chien-Ming Wang, the Nats never signed any major players from Asia.
Singer is also a former big leaguer who won 20 games for the Dodgers and Angels in 1969 and '73, respectively.
Johnson worked for the Nationals for three years and has been doing advanced scouting since 1997. According to the source, the Nats will now have a video coordinator take care of advanced scouting.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All theTime. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.