The Phillies reassigned Walker to minor-league camp Tuesday.
Walker had been attending big-league spring training as a non-roster invitee after landing a minor-league deal with Philadelphia in December. The lack of a 40-man roster spot may have worked against Walker in his bid for a spot in the Opening Day bullpen, as he otherwise made a strong case for breaking camp with the Phillies by striking out six and allowing just seven baserunners over 7.1 scoreless frames in Grapefruit League play. Walker will likely report to Triple-A Lehigh Valley.