Washington Nationals at San Diego Padres

     The Nationals and Padres dressed in 1936 uniforms - the Nationals as the Washington Senators and the Padres as the PCL Padres.  Padres announcer Dick Enberg continuously remarked on the throwback uniforms, even saying the Padres looked almost liked the Yankees with the pinstripes, and when #7 Chase Headley was up, Enberg said, it almost "looks like Mickey Mantle is up at bat."  And he later said these old uniforms reminded him of Camile Pascaul, Harmon Killebrew and Wayne Terwillinger. 
     For their credit, the players appeared to mostly be wearing them well, with stirrups and no pajama pants anywhere in sight.  Robert Marshall would be proud.

Washington Nationals at Baltimore Orioles

The Orioles, honoring the 30th anniversary of their 1970 World Series championship, defeated the Nationals, who were dressed as the 1963-71 expansion Senators who would later become the Texas Rangers. Before the game Earl Weaver was "thrown out" of the game as he accompained interim manager Juan Samuel to home plate with the lineup card.

Washington Nationals at Cleveland Indians

Pittsburgh Pirates at Washington Nationals

St. Louis Cardinals at Washington Nationals

Source: Nats320 - A Washington Nationals Blog

Washington Nationals at Milwaukee Brewers