During his sophomore year in 2013, Clark was moved to left tackle to replace All-Big 12 and current New England Patriots player LaAdrian Waddle. Prior to the beginning of the season, Clark was named a pre-season All-Big 12 selection, and was placed on the watchlists for the Outland Trophy and the Lombardi Award. Following the conclusion of the season, Clark earned Associated Press All-Big 12 1st team honors.