The Phillies selected Grullon's contract from Triple-A Lehigh Valley on Sunday.
The clear No. 3 option on the depth chart at catcher, Grullon isn't expected to function as anything more than an emergency option behind J.T. Realmuto and Andrew Knapp. The 23-year-old batted .283 with 21 home runs and 77 RBI in 457 plate appearances with Lehigh Valley this season.