The Nationals selected Chaparro's contract from Triple-A Rochester on Tuesday, Jessica Camerato of MLB.com reports.
Acquired from the Diamondbacks in the Dylan Floro trade, Chaparro is receiving his first major-league promotion after slashing .328/.405/.572 with 23 home runs over 105 games in 2024 at the Triple-A level. The 25-year-old is expected to play regularly while alternating with Juan Yepez at first base and designated hitter. Chaparro is starting at first base and batting sixth Tuesday in Baltimore in his major-league debut.