>>282
https://operations.nfl.com/the-rules/2017-nfl-rulebook/#section-4-legal-and-illegal-contact-with-eligible-receivers

ARTICLE 2. ILLEGAL CONTACT WITHIN FIVE YARDS
Within the five-yard zone, if the player who receives the snap remains in the pocket with the ball,
a defender may not make original contact in the back of a receiver,
nor may he maintain contact after the receiver has moved beyond a point that is even with the defender.

ARTICLE 3. ILLEGAL CONTACT BEYOND FIVE-YARD ZONE
Beyond the five-yard zone, if the player who receives the snap remains in the pocket with the ball,
a defender cannot initiate contact with a receiver who is attempting to evade him.
A defender may use his hands or arms only to defend or protect himself against impending contact caused by a receiver.

＞ if the player who receives the snap remains in the pocket with the ball

スナップを受けたプレーヤー(通常QB)がポケットの中にいる場合
守備側から当たればイリーガルコンタクトになる　を言い換えれば、
QBがポケットから出ればイリーガルコンタクトにならないってことでしょう