Tampa was 3-1 when the Lions played them and the Lions were without Montgomery, Gibbs and Jackson. After the Detroit game, they struggled for a while before beating some mediocre teams at the end.
Looking at who they've beat in their final 6 when they went 5-1, it was Carolina twice and not convincingly, Atlanta in a close game, a reeling Jacksonville team and a win at Green Bay.
I hate Patricia as much as anyone, but the defense was bad before Patricia started calling plays. That's the reason he's calling plays. Also, Patricia didn't design the defense.