According to the league, Adams suffered a concussion and spent the night in a hospital.
Trevathan was penalized for a helmet-to-helmet hit, delivered as Adams was being tackled by Adrian Amos after a catch. He was not ejected from the game by officials. The league can follow up with a fine or suspension after its review.
The NFL enacted a directive by its rulemaking competition committee in the offseason calling for ejections and suspensions for the most egregious of illegal hits, even on a first offense.
Lockhart said the league is withholding judgment for now on whether it believes Trevathan should have been ejected.
“I want to let the process run its course,” he said. “I will tell you our commitment to this [player-safety measures] is the same as it was yesterday.”
Mike Pereira, the NFL’s former vice president of officiating and now a rules analyst for Fox, wrote on Twitter: “That[‘]s the first time I have seen the foul called for hitting the runner with the crown of the helmet. I would eject him now.”
Dean Blandino, the other former NFL officiating chief who now works for Fox, wrote on Twitter that he “won’t be surprised” if Trevathan is suspended.
The NFL suspended Cincinnati Bengals linebacker Vontaze Burfict, a repeat offender, for an illegal hit during the preseason. Burfict’s suspension originally was for five games but was reduced to three on appeal.
Players on the field immediately waved for the medical staff to come out to assist Adams. Adams gave a thumbs-up signal before leaving the field. He was taken to a nearby hospital for evaluation and the Packers said later that he was conscious and had movement in his extremities.