‘The Pats have lost six defensive backs for the season due to injury, and that has hurt their effectiveness in mixing their coverages in some games. “A year ago, they would have guys play in different positions but doing the same thing, meaning a linebacker would take the place of a strong safety, for instance,” said tight end Mark Campbell. “At times it might screw up your calls or could make blocking schemes tougher. You don’t see as much of that.”‘