Frank Howard, of course, never played for the Nationals. Personally, I don't really understand the Nationals. When it was clear the Expos were moving to Washington, the management seemed to want to distance themselves from both the Expos and Senators franchise histories. Nationals Park, however, has statues of Walter Johnson of the first Senators franchise, Frank Howard of the second Senators franchise, and Josh Gibson of the Homestead Grays. The Grays were based in the Pittsburgh area but from 1940-1950 they played half of their home games in D.C.
With all the statues to chose from at AT&T Park, I had to go with the trademark leg kick of Juan Marichal. Marichal was a ten-time all-star for the Giants. He had 2 All Star wins and gave up only 1 earned run in 18 innings.