Walker will not make his scheduled start Sunday against the Phillies, Steve Gilbert of MLB.com reports.
Randall Delgado is now slated to toe the rubber opposite Jeremy Hellickson. Manager Torey Lovullo said the decision to scratch Walker has nothing to do with an injury; rather, the team simply wants to give Walker a bit of a break. Walker has made two starts since returning from a blister issue, allowing four runs while striking out 14 over 11 innings. He totaled 149.1 innings between Triple-A and the majors last season.