Kratz, 39, was one of the key players in the Brewers' National League Division Series win over the Colorado Rockies, going 5-for-8 with two RBIs. But he was in a camp competition with Manny Pina for the backup catcher spot behind Yasmani Grandal and lost out.
"I found out Feb. 1 I wasn't going to make the team," Kratz told reporters, according to the Journal Sentinel. "It's nice to finally get that resolved. It's bittersweet though. You lose out on spending time with guys you made a connection with.
"There are plenty of memories. Just seeing my teammates celebrate on the field after (Game) No. 163. Hearing the fans all through the playoffs. It was something that was really cool to be a part of. It's something I'm never going to forget. Now, I've got to move on to the next team."
The Brewers officially signed reliever Alex Wilson to fill Kratz's roster spot. The team had agreed to a contract with Wilson last week with right-hander Corey Knebel out indefinitely after suffering a partial tear to the ulnar collateral ligament in his pitching elbow and fellow right-hander Jeremy Jeffress sidelined with a sore shoulder. Wilson, also a right-hander, has pitched the past four seasons with the Detroit Tigers and had a 3.36 ERA in 61 2/3 innings last season.
The Giants have been active the past two days with trades as they work to set their opening 25-man roster. On Saturday they traded outfielder Matt Joyce to the Atlanta Braves for cash considerations and acquired outfielder Michael Reed from the Minnesota Twins for outfielder John Andreoli and cash.
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 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.
The Associated Press contributed to this report.