Walker's foot injury stems from him having extremely flat feet, which puts pressure on his tibia, but the Mariners are confident orthotics inserts in his shoes will solve the problem, the Seattle Times reports.
Walker aggravated the injury in his last start when he charged off the mound to field a bunt. He then couldn't use his leg to push off during his windup. The Mariners hope the shoe insert will arrive in time for his Sunday start. If not, Walker will pitch with his foot taped and hope he doesn't aggravate it again.