NFL officials and Miami Dolphins medical staff will face tough questions, after star quarterback Tua Tagovailoa was stretchered off the field with a scary head injury during his team's clash with Cincinnati Bengals.
Tagovailoa, 24, was taken to hospital, after he was sacked by Cincinnati's Josh Tupou and swung to the ground violently. His head and upper back hit the turf hard, and his fingers spasmed in an odd manner.
He stayed on the ground for a few minutes, as trainers attended to him, before he was taken off the field on a stretcher.
"Tua Tagovailoa has been taken to a local hospital for further evaluation. He is conscious and has movement in all his extremities," the Dolphins tweeted.
Only four days earlier, Tagovailoa was evaluated for a concussion during the Dolphins win over Buffalo. He looked unsteady as he left the field, but reportedly passed the league-mandated concussion protocol at halftime and was allowed to return to the game.
He was not placed in the concussion protocol after the game, but was regarded as 'questionable' for the Bengals game, with the Dolphins categorising his injuries as back and ankle niggles.
The NFL confirmed it would investigate whether protocols were followed, but believed they were.
"Player health and safety is at the core of the union's mission," said the NFL Players Association, after the most recent incident. "Our concern tonight is for Tua, and we hope for a full and speedy recovery.
"Our investigation into the potential protocol violation is ongoing."
Dolphins coach Mike McDaniel insists he would not have put Tagovailoa on the field with ongoing concussion concerns.
"The one thing I think our players know more than anybody, there's certain things that I'm very sensitive to," he said. "I've been called emotional from time to time and one of those things is player health, so I don't mess around with that at all.
"They went through the protocols and in that process during the game, and it was something that we wouldn't have moved forward in the direction we did, had there been any sort of red flags... if he had a head issue, he wouldn't have been back out there."
Tagovailoa entered the NFL under an injury cloud, after suffering a dislocated hip, fractured posterior wall, broken nose and concussion in 2019, while playing for Alabama University against Mississippi State University.
He forwent his final year of college eligibility to enter the 2020 NFL draft, where the Dolphins selected him with the fifth pick.