The Athletics recalled Estes from Triple-A Las Vegas on Friday, Jason Burke of Roundtable.io reports.
Estes has mostly struggled in the harsh pitching conditions of the Pacific Coast League this season, posting a 6.88 ERA and 1.64 WHIP over 86.1 innings with Las Vegas. He has worked exclusively as a starter this year, and while he figures to be available out of the bullpen immediately upon his return to the majors, Estes could make a start next week in place of Jack Perkins, who was sent down in a corresponding move.