Realmuto is out of the lineup for Thursday's game against the Brewers.
The Phillies will give Andrew Knapp a turn behind the plate in Realmuto's stead while the team concludes its series with Milwaukee with a day game after a night game. Realmuto has assumed one of the heaviest catcher workloads in the league, manning the position in 36 of the Phillies' first 42 games.