Colts safety Shamarko Thomas became the unwitting test case for the new helmet rule, as he was ejected in the fourth quarter of the first preseason game against the Seahawks. The helmet-to-helmet contact foul is the first ejection of the 2018 season.
Thomas’s hit is in a rare category. Football Zebras and Quirky Research have determined that the last time an ejection was assessed for an in-play hit — not including fighting, punching, etc. — was a flagrant fair-catch interference hit by Panthers cornerback Dante Wesley on Oct. 18, 2009 (video).
— Alex Kozora (@Alex_Kozora) August 10, 2018
As a technical matter, this is a hit on a defenseless receiver, which has been a foul for many years. What is different is any use of the helmet to initiate contact falls under new ejection criteria. The new rule has removed the words if flagrant from the rule, and allows for a wider interpretation of an ejectable offense.
For the 2018 season, it is an ejection if:
Player lowers his helmet to establish a linear body posture prior to initiating and making contact with the helmet
Unobstructed path to his opponent
Contact clearly avoidable and player delivering the blow had other options
All three criteria are present in the Thomas hit.
Because of the complexity of factors (which have to be retroactively determined after the helmet hit), the officiating command center can make an ejection determination when a flag is thrown. There is no replay intervention if no foul is called, and this is separate from any other replay functions. During the season, if you see officials having an extended discussion, they are probably in contact with the command center through their wireless headsets to get an ejection decision.
But, there is a clear indication on how tightly the helmet hits will be called, as the first ejection in the league comes before some teams have even played a single preseason game.