The Nationals recalled Chaparro from Triple-A Rochester on Tuesday.
Chaparro made Washington's Opening Day roster but played in only three games before being demoted to Rochester, where he's remained except for a one-day stint with the Nationals in late April. He's gone 2-for-9 with a walk and a double in the big leagues and has an .801 OPS with six homers in 35 games at the Triple-A level this season.