NBA规则视图文解析：掩护犯规八例之1-3

挡拆掩护犯规（Screens & Picks）
违规掩护（Illegal Screens）
挡拆掩护战术（Pick'n Rolls）
掩护犯规之一：挡拆战术中，掩护者阻挡防守球员前进路线，未给其留足停顿和变向机会，属进攻犯规
Illegal Screen, Pick'n Roll, Screener rolls into defender

Commentary:
This is an example of an offensive foul for an illegal screen set in a pick'n roll situation. An offensive player may not get into the path of a moving defender without giving him the opportunity to stop and/or change direction. The distance needed to be given will depend on the speed of the opponent. On this play, the screener impedes the trailing defender by rolling right into the path of that defender without giving him the opportunity to stop or change