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 more traction in the lineup versus right-handed pitching lately. He'll crack the starting nine against a righty (Janson Junk) for the third time in four games, after he went 4-for-11 with a home run, a double, a walk, three RBI and three runs over his prior three starts.