The on-ball defender’s goal is to keep the defender in front of him but help defense is available if dribble penetration occurs
The red curved line just inside and mirroring the 3-point line distinguishes the “pack” area. If a defender is not on the ball, then he is inside the pack. The boxed area is the “post” and the goal is to keep an offensive player from catching a pass with both feet in here .
HOW TO PLAY
The on-ball defender plays tightly on the ball handler. The goal is to cause chaos and confusion for the ball handler with the knowledge that help defense is available if beaten. In this instance, the ball handler dribbles hard to the left with the on-ball defender trailing. The player at the top left of the pack comes out to stop the penetration as the on-ball defender sags back into the pack. The post defenders front their responsibilities if those offensive players are in the post area . The pass is made to the wing, so the new on-ball defender jumps to the wing as the other defenders shift inside the pack .
If the ball handler picks up the dribble outside then pack line, then all defenders go into full-deny mode. Otherwise, they remain in the gap and available to provide help defense, which cuts off dribble-drive opportunities and cuts down highpercentage shots.