Ward, who was considered part of the blame to the Sox' early struggles offensively, making them 12th in the AL in both runs (173) and batting average (.249), was fired after Sunday's 3-2 loss to the Twins.
Walker, 43, was a former White Sox first baseman who had a career .260 batting average, and drove in 444 RBIs, while hitting 113 homers. Down in Charlotte, he helped the Knights to a league-leading .285 batting average this season.