The Giants released Haase on Wednesday, Justice delos Santos of The San Jose Mercury News reports.
The 33-year-old was in camp as a non-roster invitee and hit well during spring training with a .911 OPS in 18 games, but the Giants will begin the year with Daniel Susac as the backup catcher to starter Patrick Bailey. Haase spent the past two seasons in Milwaukee and posted a .229/.289/.357 slash line across 77 plate appearances during the regular season last year.