On Midline Lead, the Backside A-back needs to come over from the backside to the playside in order to serve as the extra blocker and lead the way for the Quarterback.
He does this during the cadence.
1- The cadence is Down, Ready, Sethut (ball snapped on “S” of sethut)
2- The A-back leaves on the Down by hammer stepping with his inside foot, and then driving his outside foot pointing in a direction five yards behind the Quarterback.
3- He runs to get five yards behind the Quarterback by the “S” in sethut.
4- On the “S” in sethut, the Playside A-back steps with his playside foot through the inside leg of the Playside Tackle and runs through the inside leg of the Playside Tackle as fast as he can.
5- The Playside A-Back will block any 2nd level defender who shows in that gap. If nobody does, he will continue running and block the near safety. He does not have to win any leverage points. The goal is a tremendous collision.
This is how the extra blocker is brought to the Playside on Midline–this is required vs. a 3-technique and a playside safety.