Reactions on social media were swift following the hit – which occurred during the final seconds of the Thursday Night Football game after Garrett sacked Rudolph. The encounter ended with players from both teams jumping in to defend their teammates, resulting in ejections for both sides and possible additional suspensions .

On Twitter, many users expressed shock that Garrett would use his helmet in such a way, saying it was the first time they had seen such a display. However, this isn’t the first time that a player has used a helmet to attack another in the NFL.

During the broadcast, Mike Pereira, a Fox rules analyst and former President of Officiating for the NFL, pointed out that taking a player’s helmet off and using it as a weapon is written in the NFL rule book. An ESPN reporter also pointed out the specific rule on Twitter.

“A player must not use a helmet that is no longer worn by anyone as a weapon to strike, swing at, or throw at an opponent,” the NFL rule book states.

Following the incident, Newsweek looked into other times that this type of action has happened in the NFL.

The rule was put into place following a 1982 playoff game between the Oakland Raiders and New York Jets. During the game, Raiders’ defensive lineman Lyle Alzado ripped the helmet off of Jets’ offensive lineman Chris Ward and attempted to throw it at him.

Since there was no rule in place saying a player could not use a helmet as a weapon, the refs charged Alzado with unsportsmanlike conduct, but subsequently, the ‘Lyle Alzado’ rule was created the following offseason.

Another incident happened in 2002 during the Kansas City Chiefs training camp. During a team practice, a fight broke out between defensive lineman Eddie Freeman and offensive lineman John Tait. Freeman hit Tait with his own helmet causing 17 stitches and a broken nose.

“He had my helmet and hit me with it. It wasn’t his fist,” Tait told reporters after the incident. “It’s common knowledge he had my helmet in his hand, and he swung it back and hit me with it.”

In 2006, Tennessee Titans defensive end Albert Haynesworth was suspended for five games after he knocked the knocked off Dallas Cowboys center Andre Furode’s helmet and kicked him in the face. Haynesworth did not use the helmet as a weapon, but his suspension length could give insight into how the league will handle Garrett’s situation.

NFL Network reporter, James Palmer also pointed out another instance where a player used a helmet as a weapon in 2013. During a preseason game, Houston Texans defensive end Antonio Smith ripped the helmet off of Miami Dolphins’ guard Richie Incognito and tried to hit him with it.

According to the play-by-play record of the game, no penalty was called on Smith, but he was later suspended for the final two games of the preseason as well as week one of the regular season.

Following Garrett’s helmet hit on Rudolph, he was ejected from the game, and many have been speculating what type of suspension could come. During the broadcast, Pereira stated that he believed Garret could receive a suspension up to four games.

Some other NFL insiders believe that Garrett would receive a much harsher punishment.