There are several rules that can be applied to this illegal screen, which is a must call when the result is an open shot attempt.
Rule 4-40 deals with what is and isn’t legal in setting a screen. In the following play, there are actually several key articles that are violated to make this an illegal screen.
Article 1 states, “A screen is a legal action by a player who, without causing contact, delays or prevents an opponent from reaching a desired position.” So, this means that when there is contact, judgments need to be made to determine if either player did something wrong which causes the contact. Article 2c states that the “screener must be stationary, except when both the screener and opponent are moving in the same direction.”
For this play, there is also consideration to Article 4 which deals with screens set outside the visual field of the opponent. When the screen is set outside the visual field, the screener must allow one normal step backward without contact.
In this video, the screener sets a screen outside the visual field, takes a step into the opponent, and then continues to move the opponent in the opposite direction. The result of this screen is an open 3-point attempt. The ruling of an illegal screen is a must call in this situation.