The five: Trot Nixon and Lou Merloni of the Boston Red Sox, MarlonAnderson of the Philadelphia Phillies, Torii Hunter of the Minnesota Twins and Gabe Kapler of the Detroit Tigers.
Unfortunately, the significance of this honor has waned since the Nationals have issued the number eight to players such as MarlonAnderson (2006), Chris Snelling (2007), Aaron Boone (2008), and Jorge Padilla (2009).