The Panthers' front four must be dynamic for their zone coverages to work. In 2016, Carolina was 3–1 in games in which the D had at least four sacks, and 3–9 in games it didn't. In 2017 sacks will likely come from guys who aren't currently on the roster. Defensive tackles Kawann Short and Kyle Love (combined: 7.5 sacks) are free agents. At defensive end, the free-agent list includes Charles Johnson, Wes Horton and Mario Addison (16 total), and next year Kony Ealy (five) could walk. Of these players, only Short is a must re-sign—and that may be tough without franchise-tagging him. GM Dave Gettleman has lamented the defensive-tackle-market-setting contract signed by the Eagles' Fletcher Cox last year: six years, with $63.3 million guaranteed.