Mystery Theme IV: Back To School by KlionskyG

Question 3

"Because the act [...] often puts the quarterback [...] in a position where he is particularly vulnerable to injury, special rules against ______________ apply."

What phrase fills in the blank in the above sentence, excerpted (and slightly redacted) from Rule 12, Section 2, Article 11 of the NFL rulebook?

Roughing the passer (GHI)