‘Walker, 23, joined the Bills as an undrafted free agent. In college, Walker played for the Louisville Cardinals, Oklahoma Sooners and Arkansas Razorbacks. During his stop with the Sooners, Walker played for Bills cornerbacks coach Jay Valai. Valai served as Oklahoma’s co-defensive coordinator and kept tabs on his former player throughout the draft process. Valai’s contact with Walker leading up to the draft helped Buffalo land the cornerback post-draft.’