The Giants signed Knapp to a major-league contract Friday, Susan Slusser of the San Francisco Chronicle reports. He's catching and batting ninth against the Mariners on Friday.
Knapp hasn't seen any MLB action since 2022, spending the 2023 season at the Triple-A level in the Astros and Tigers organizations and appearing in 81 games for the Rangers' Triple-A affiliate this season before opting out of his minor-league deal July 1. He slashed .294/.383/.457 at Triple-A this year and will serve as the backup to Curt Casali while Patrick Bailey (oblique) is on the shelf. Bailey is expected to return by the end of August.