 Its purpose is to stop secondary defenders from taking a position under the basket in an attempt to draw the offensive foul when a player is driving to the basket . If an offensive player drives past his primary defender on the way to the basket and a secondary defender comes over , he must establish a legal position outside the RA to draw an offensive foul . If the drive starts inside the Lower Defensive Box ( <unk> – this is the area from the bottom tip of the free throw circle to the end line between the two 3 ’ posted @-@ up marks ) , the secondary defender is legally allowed to be positioned inside the RA . The restricted area also does not apply if the secondary defender jumps in attempting to block the shot , the offensive player leads with his leg or knee in an unnatural motion or uses his off arm to prevent the defender from blocking his shot . The RA does not extend from below the <unk> to the baseline . Therefore , if a player drives the baseline and is not attempting to go directly to the rim , the RA does not apply . 
