Bill Foster Defensive Transition Drill

Defender 1, hands or short passes the pass to the offensive player.
The defender then sprints to half court then back to the ball handler advancing the ball back up the court.
The defender gets their head and shoulders in front of the ball, forcing the ball carrier to change their path.
Once the offensive player scores at the opposite end, the roles change and the offense becomes the new defense.

The defense wants:
get head and shoulders in front of the ball at speed.
force the ball handler change their path - to the sideline.
play in a low defensive stance - all the way.