Illegal Screen in Basketball: Basic Information Explained

What is general information about the illegal screen in basketball

Basic definition of illegal screen

An illegal screen in basketball comprises action that generally occurs when a offensive player makes prohibited contact while setting a screen and/or the offensive player does not allow an opposing defender, who would be the target of the screen, enough time and/or distance to avoid the screen.

Penalty for illegal screen

When a offensive player, who would be the screener, gets signaled for an illegal screen, particularly by a referee within organized competition, the penalty is an offensive foul charged to the screener as well as loss of basketball possession to the opposing team via turnover.

Cylinder in relation to illegal screen

A screener must stay within their own cylinder, also known as a vertical plane, approximately shoulder width apart while setting a basketball screen.

A cylinder is technically imaginary but it basically includes any area of occupied space that surrounds the screener or any other active player from the floor to as far as they can jump or extend their arms above their head.

It is also important to note that the diameter of the cylinder does not go beyond the screener’s or any other particular player’s hand/arms on the front side, the rear on the back side, or the sides of a player’s legs.

This means that the offensive player setting the screen cannot extend any body parts to delay or prevent a defender from reaching their own desired destination, which is typically near another offensive player.

Essentially, a screener cannot make contact with a defender by extending their elbows, forearms, legs, feet, or hips to obstruct that defender’s movement.

This is also the case even if the screener initially established the legal screening position, which generally consists of feet about shoulder width apart, back straight, and knees slightly bent to form a good base.

In short, if a screener does not remain within their own cylinder, particularly by using parts of their body to make contact with a defender, then that is effectively an illegal screen.

Related: Basketball rules – FIBA

Time and/or distance in relation to illegal screen

An offensive player setting a screen must give the defender enough time and/or distance to avoid the screen by going over the top or under the screen.

The time for the defender to go over the top or under the screen is usually determined by the speed of that same defender.

Additionally, the distance for the defender to go over or under the screen is usually at least one or two steps.

In short, if a screener does not give time and/or distance so that a defender can avoid the screening action, then that is an illegal screen.

Moving screen in relation to illegal screen

A moving screen is a colloquial term that is sometimes utilized when a screener makes prohibited contact with a defender by moving their feet or other parts of their body while that same defender is simultaneously attempting to avoid a screen, primarily by going over or under it.

Nevertheless, the moving screen is still an illegal screen because the screener either does not remain within their own cylinder or give the defender enough time and/or distance to avoid the screen.

Additionally, a screener could swiftly move their feet to re-establish a screen if necessary. However, it is important to note that the screener must still give the defender enough time and/or distance prior to that same defender making contact with the screen.

A situation like this may occur with certain types of screening actions, most notably the stagger screen.

For example, with the stagger screen action, a defender may successfully avoid the first screener but immediately afterwards, it is possible for the second screener to move slightly to re-establish that second screen.

As long as the second screener stays within their own cylinder and gives the defender enough time/distance to avoid the screen, it would be considered legal.

However, if the second screener were to move, particularly during the moment when the defender makes contact with the screen, then that would be an illegal screen, which could also be informally referred to as a moving screen.

Again, in that scenario, the second screener must give the defender enough time and/or distance to avoid that second screen as part of the stagger action. Otherwise, the screening contact would be illegal.

Simple strategies that offensive players could use to limit or prevent setting illegal screens

In terms of an on-ball screen, the screener should set both feet first about shoulder width apart, sometimes with a jump stop if necessary, and remain stationary until the defender clears the screen.

Also, the offensive player who would be the recipient of the on-ball screen should wait for the screener to set their feet prior to dribbling in the vicinity of the screen.

Basically, if the recipient of the screen utilizes it too early, especially before the screener is fully set, then that could lead to an illegal screen.

That would also result in the screener being charged with an offensive foul as well as loss of basketball possession to the opposing team.

In terms of an off-ball screen, the screener should have their feet set shoulder width apart while remaining stationary similar to the on-ball screen.

However, the screener should definitely give the defender enough time/distance to avoid the screen, especially if the screening action is initially outside of the defender’s field of vision, which could happen in the case of a back screen or possibly cross screen.

Moreover, as a side note, the off-ball screener typically should not attempt to set a screen on or over the baseline in the frontcourt, which is also the out of bounds area.

This may occur in certain situations such as when an off-ball offensive player is using a pin down screen near the baseline and at the same time, a defender is chasing behind that offensive player.

Basically, if the defender runs out of bounds to avoid the screening action, then the adjacent screener should not also step out of bounds to block or delay that defender.

If that occurs, then it would usually result in a violation and subsequent penalty of the offensive team losing possession of the ball via turnover.