The Brewers designated Ornelas for assignment Tuesday, Adam McCalvy of MLB.com reports.
The 26-year-old was acquired from the Athletics in mid-August but made just three appearances for the Brewers before losing his place on the 26-man and 40-man rosters. Between his time in Sacramento and Milwaukee this year, Ornelas has gone 4-for-21 with 11 strikeouts in nine MLB contests.