Per ESPN's Jeff Passan, Realmuto is expected to miss up to one month with the injury but should be ready for the start of the regular season.
Realmuto returned to the Phillies in free agency this offseason, signing a five-year, $115 million contract Jan. 27.
He was an All-Star and Silver Slugger in 2018 with the Miami Marlins and again in 2019 with the Phillies. He was also a Gold Glove winner in 2019, his first season in Philadelphia.
The 29-year-old slashed .266/.349/.491 with 11 home runs and 32 RBI during the shortened 2020 campaign and brings more power to the lineup than most catchers while also playing impressive defense.
The silver lining to Realmuto's injury is that he has time to return to 100 percent before the season starts. The Phillies open the 2021 campaign April 1 against the Atlanta Braves.
With Realmuto out of action, the Phillies will turn to Andrew Knapp as their primary catcher during spring training.