The 30-year-old Schierholtz batted .192 with six homers and 33 RBIs in 99 games for the Cubs this season before being released on Aug. 13, but is only one year removed from his finest offensive season in an eight-year career.
In 2013, Schierholtz batted .251 with 32 doubles, 21 homers and 68 RBIs. Schierholtz, who spent the first six years of his career with the Giants, is a career .254 hitter with 51 homers and 223 RBIs.
Primarily a right fielder, Schierholtz can play all three outfield spots and swings from the left side of the plate. He will report to Triple-A Syracuse and seems destined to be summoned to the Nationals when rosters expand on Sept. 1.
Schierholtz has played in 11 postseason games and earned World Series rings in 2010 and 2012 with the Giants.