Dean was designated for assignment by the Giants on Sunday, Evan Webeck of The San Jose Mercury News reports.
The 28-year-old was claimed off waivers by the Giants in November, but he's now been removed from the 40-man roster to make room for the signing of Matthew Boyd. Dean appeared in 22 games for the Cardinals last season and hit .233/.342/.400 with one home run and seven RBI in 38 plate appearances.