The Giants claimed Rojas off waivers from the Angels on Sunday and optioned him to Triple-A Sacramento, Maria I. Guardado of MLB.com reports.
San Francisco cleared a spot on the 40-man roster for the veteran utility man by transferring Brandon Belt (knee) from the 10-day injured list to the 60-day IL. Before the Angels designated him for assignment Thursday, Rojas had logged 57 plate appearances at the big-league level this season, slashing .125/.140/.161 while striking out at a 33.3 percent clip.