There was a scary moment after a tackle on Thursday night in Cleveland.
Late in the second quarter, Browns' Elijah Moore was tackled from behind on a routine play, but he went to the ground awkwardly.
The receiver fell helmet-first into the playing surface, and then he turned onto his back.
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While he lay, Moore's head shook back and forth, which at first seemed like Moore just shaking off the hit. But then, his arms began flailing.
His arms were not moving violently, but they did look as if Moore had no control over them, prompting a teammate to call for the training staff.
The Amazon Prime Video broadcast was quick to change camera angles.
Trainers were to be on Moore's side swiftly, but he eventually walked off the field with some help - he did not return to the game, after the Browns said he suffered a concussion.
Dr. Evan Jeffries, who is on X, formerly Twitter, as the "@GameInjuryDoc," said Moore's movements were "involuntary…from a brain injury."
Another doctor, Jesse Morse, said Moore may have suffered a seizure.
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Moore made five receptions for 61 yards and a touchdown against his former New York Jets before the injury.
The Browns had already been without Amari Cooper, who had 265 receiving yards last week, due to a heel injury.
The Browns had not provided a further update beyond the concussion notice at the time of publishing.
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