Millas is starting at catcher and batting eighth in Tuesday's matchup with the Dodgers, Andrew Golden of The Washington Post reports.
Millas was called up Monday to help Riley Adams handle the backstop duties while Keibert Ruiz (illness) is on the 10-day injured list. Millas has made one start with Washington this season, going 1-for-3 with a stolen base in the team's 7-1 loss to the Giants on April 10.