Chaparro will start at first base and bat seventh in Sunday's game against the Marlins.
Since being called up from Triple-A Rochester on May 19, Chaparro has largely served as a short-side platoon player for the Nationals, but he's begun to gain traction in the lineup versus right-handed pitching. He'll crack the starting nine against a righty for the third time in four games, and on the season he sports a 1.127 OPS with three homers in 35 plate appearances in that split.