The Dallas Cowboys have been dealing with some major injuries to their defensive unit in the past few weeks. Unfortunately, on Sunday Night Football against the Pittsburgh Steelers, things got worse for the franchise. Dallas rookie defensive end Marshawn Kneeland was carted to the locker room, according to the NBC broadcast. He twisted up his right knee a bit while trying to make a tackle. Kneeland couldn’t put much pressure on his right leg as he was helped to the medical tent. During the broadcast, NBC sideline reporter Melissa Stark updated his status. “Mike you mentioned the Cowboys came t…