The Giants designated Reetz for assignment Friday, Maria I. Guardado of MLB.com reports.
Reetz was recalled from Triple-A Sacramento on Tuesday to provide catching depth while Patrick Bailey (oblique) was on the injured list. He hasn't appeared in a game since then, and he'll now lose his roster spot to Andrew Knapp, who signed with San Francisco on Friday. The 28-year-old Reetz owns a .254/.368/.431 slash line through 235 plate appearances in the minors this season, which could draw some interest from other teams in need of organizational depth behind the dish.