Matthews was flagged in the fourth quarter of Sunday's 29-29 tie with the Minnesota Vikings after referee Tony Corrente said the six-time Pro Bowl selection "lifted (quarterback Kirk Cousins) and drove him into the ground."
The penalty denied a potential game-clinching interception by Jaire Alexander with under two minutes remaining in regulation. The 15-yard penalty kept the drive alive, and the Vikings scored a touchdown and added a two-point conversion to effectively send the game to overtime.
NFL's Senior Vice President of Officiating Al Riveron plans to "reiterate that this tactic is a foul," ESPN reported of Matthews' hit on Cousins.
According to Rule 12, Section 2, Article 9, the NFL rulebook reads in part that: "A rushing defender is prohibited from committing such intimidating and punishing acts as 'stuffing' a passer into the ground or unnecessarily wrestling or driving him down after the passer has thrown the ball ..."
The NFL considers such fouls to be judgment calls and they are not subject to replay review.
"(Matthews) did what he was coached to do," Packers coach Mike McCarthy said on Monday.
Matthews told reporters on Sunday that he had no idea why the flag was thrown.
"Like I said, I got my head across, hands were down, didn't dump him, hit him within the framework, proper tackling area. I don't know," the 6-foot-3, 255-pound Matthews said. "Much like you saw with the lowering the helmet (rule) in preseason, I think that hopefully the league gets to the refs and tells them to tone it down a bit, because I don't know what else to do."