Worth every penny. Without Mack our D is a big 'ol ? mark, with him he puts one side of the Dline on mother f'n lock-down and allows others to do their thing. Heart and PJ Hall in the middle and Key on the other side, as well as others. Cornerstone of the D. Salary cap goes up every year, it'll work out somehow, someway. You don't let players like Mack get away from you.