Why would a zone defense play call not shut it down? Please educate
In Cover4 there are provisions to trade assignments. In standard Cover4, the corner will observe the #1 receiver, who is closest to the sideline. If the #1 releases to a slant pattern, the corner should know that a complimentary pattern is coming his way. Corner releases the #1 to the safety. The safety will observe the #2, second from sideline. If #2 runs the sideline pattern he trades coverage with the corner thus no pick is executed because the safety is now covering the #1 who is picking or rubbing him. The corner is now laying in wait for the #2 or inside receiver.
Some programs have both the corner and safety read the #2. This is a check called 2 read Cover4. Remember the #1 and #2 receivers are aligned for the pick play. They are too close to execute the quick slant pattern therefore the corner plays the #2 first and the #1 second therefore corner is laying in wait for the #2. When the #1 tries to pick the safety, the safety reverses the situation and blows up the #1 with the corner waiting for the #2.
Maybe the secret is to this is to play man like Alabama sometimes, then add standard Cov4 and some 2 read Cov4. Hope this is an acceptable answer.