Getty Defensive back Jermod McCoy #3 of the Tennessee Volunteers could be crossed off the list of Dallas Cowboys draft prospects. If there is anything that could be said for sure about how the Dallas Cowboys should approach their defensive rebuild under new coordinator Christian Parker, it is this: They need cornerbacks. Yes, the Cowboys need a linebacker. That’s true every year, it seems. And yes, they’ll need help at safety and will seek to bolster the pass rush as well. But of all the