Adams will serve as the Mariners' opening pitcher for Thursday's game against the Astros, Greg Johns of MLB.com reports.
Seattle will experiment with an opener for the first time this season, with Adams pitching ahead of bulk reliever Tommy Milone in the series finale. Adams hasn't covered more than two innings or tossed more than 33 pitches in any of his relief outings this season, so those likely represent the upper bounds of his workload Thursday.