Giants president of baseball operations Farhan Zaidi had wanted an experienced catcher to provide depth behind Buster Posey, who is back from right hip surgery that ended his 2018 season in late August.
The 38-year-old Kratz batted .236 with six home runs and 23 RBIs in 67 games for the Brewers last season, hitting .292 in nine playoff games. He joins his eighth team over 10 major league seasons.
The Giants reassigned catcher Stephen Vogt to minor league camp. He is working his way back from surgery on his troublesome right shoulder last May and didn’t play for Milwaukee last year.
Vogt reached a minor league deal before spring training along with Rene Rivera, just released by the Giants.