Lyles will not start Tuesday's game against the Athletics as previously expected, Chris Halicke of SI.com reports.
Taylor Hearn will start on the mound instead in what figures to be some form of a bullpen game for the Rangers. Manager Chris Woodward cited giving Lyles a rest as the main reason for the change, though he also noted that the right-hander's struggles this season also played a factor. Lyles, who holds a subpar 5.68 ERA on the campaign, will be available out of the bullpen Tuesday, though it's not clear if the plan is for him to provide length immediately after Hearn departs.