Zunino the third selection overall, was hitting .238 with 11 home runs and 43 RBIs for the Rainiers when he was called up Tuesday.
General Manager Jack Zduriencik said "we had a little bit of a later target date" for Zunino's arrival but the team was in a personnel bind. Backup catcher Jesus Sucre injured his hand June 4 and the club called up Double-A catcher Brandon Bantz as a short-term replacement.
Sucre then needed more time to heal and was placed on the 15-day disabled list Thursday. That's when the Mariners believed they needed a longer term solution.
Bantz, who played one game, was designated for assignment to make room on the 40-man roster.