Millas went 1-for-3 with a solo home run in Wednesday's 7-6 loss to the Pirates.
Millas cut the Nats' deficit to 7-2 with the first homer of his big-league career, a 405-foot blast off Quinn Priester in the fifth inning. The 25-year-old backstop has hit well in limited action since he was recalled Aug. 28, going 4-for-12 with four RBI. Millas should continue to back up Keibert Ruiz down the stretch with Riley Adams (hand) out for the rest of the season.