The NFL and NFLPA have concluded their investigation regarding Tua Tagovailoa's injury on Sept. 25 when he showed gross motor instability.

The investigation showed the following:

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Tua Tagovailoa gets taken off the field

Miami Dolphins quarterback Tua Tagovailoa is helped off the field during the first half against the Buffalo Bills on Sept. 25, 2022, in Miami Gardens, Florida. (AP Photo/Rebecca Blackwell)

"While the investigation determined that the team medical staff and unaffiliated medical professionals followed the steps of the Protocol as written, the NFL and NFLPA agree that the outcome in this case is not what was intended when the Protocols were drafted."

After a tackle during a Week 3 game, the Dolphins quarterback hit his head on the turf, grabbed his helmet, shook his head several times, and took several steps before wobbling back down to the turf.

Tagovailoa and the team said he suffered a hyperextended back — not a concussion like most thought — which was concluded to be the case.

The investigation found, as the team had stated, that Tagovailoa "did not report or exhibit any signs or symptoms of concussion during his locker room exam, during the remainder of the game, or throughout the following week," and that his gross motor instability was not neurologically caused.

Dolphins gather around injured Tua

Teammates gather around Miami Dolphins quarterback Tua Tagovailoa after an injury during the first half against the Cincinnati Bengals on Sept. 29, 2022, in Cincinnati. (AP Photo/Emilee Chinn)

NFL SAYS THERE IS 'EVERY INDICATION' DOLPHINS FOLLOWED CONCUSSION PROTOCOL WITH TUA TAGOVAILOA

"However, the team physician and UNC (unaffiliated neurotrauma consultant) did not conduct an examination of Mr. Tagovailoa’s back during the concussion examination, but instead relied on the earlier examination conducted by other members of the medical staff."

With the results of the investigation came a modification in the concussion protocols that are set to be in effect for Sunday's games.

The NFL and NFLPA said that any player who shows "abnormality of balance/stability, motor coordination or dysfunctional speech caused by a neurological issue," known as ataxia, he will be unable to return to the field.

Tua lying on turf

Quarterback Tua Tagovailoa of the Miami Dolphins sits on the turf during the first half against the Buffalo Bills at Hard Rock Stadium on Sept. 25, 2022, in Miami Gardens, Florida. (Megan Briggs/Getty Images)

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There is no timetable for Tagovailoa's return.