The Mariners selected Zavala's contract from Triple-A Tacoma on Tuesday.
The Mariners will add Zavala to their active roster to provide some security behind the plate while Mitch Garver battles a wrist injury. The 30-year-old Zavala has slashed just .154/.214/.282 across 43 plate appearances in the majors this season and is unlikely to see much playing time during his stint with Seattle. Jhonathan Diaz was optioned to Tacoma in a corresponding move.