Walker is slated to start the first game of the Mariners' doubleheader with the Padres on Thursday, Greg Johns of MLB.com reports.
Walker had been in line to start Wednesday before the contest was postponed. The Mariners will keep their six-man rotation in order and have Walker take the hill for the first game of the twin bill, while Yusei Kikuchi stays on turn to pitch in the second contest. Walker, who is a prime candidate to be dealt prior to the Aug. 31 trade deadline, has posted a 4.00 ERA, 1.07 WHIP and 25:8 K:BB across 27 innings this season.