The Astros designated Thomas for assignment Thursday, Brian McTaggart of MLB.com reports.
Thomas arrived in the Astros organization via waiver claim in May, but he never made an appearance with the big club and will now lose his place on the 40-man roster to make room for the newly signed LaMonte Wade. Thomas has slashed just .253/.304/.307 across 184 plate appearances at Triple-A this season despite benefiting from hitter-friendly environments in the Pacific Coast League.