Right-handed pitcher Logan Webb has been reinstated from the injured list in a corresponding move.
Posey, 34, will enter the All-Star break with a .328/.421/.547 slash line with 12 home runs and 28 RBI.
Curt Casali should receive the lion's share of the playing time behind the plate for the Giants during the three-time World Series champion's absence. Chadwick Tromp moves into the backup role.
Posey is such a crucial cog in the middle of the San Francisco offense that any type of extended stint on the injured list would limit the club's offensive upside during the 2021 season. His impact handling the pitching staff behind the plate would also be missed.