MIAMI GARDENS, Fla. (AP) — The NFL’s concussion protocol was followed after Dolphins quarterback Tua Tagovailoa suffered an injury against the Buffalo Bills last month, the NFL and NFL Players Association concluded in a joint investigation.

The parties released a joint statement on their findings Saturday.

“The outcome in this case was not what was intended when the Protocol was drafted,” the statement said.

As a result, the NFL and NFLPA agreed to modify the league’s concussion protocol, adding the term “ataxia,” to the mandatory “no-go” symptoms. In the statement, they defined ataxia as “abnormality of balance/stability, motor coordination or dysfunctional speech caused by a neurological issue.”

If a player is diagnosed with ataxia by the team or other neutral physician, that player will immediately be ruled out of the game and will receive follow-up care.

In the first half of the Week 2 game on Sept. 25 against Buffalo, Tagovailoa took a hit from Bills linebacker Matt Milano, which caused him to slam to the ground. He appeared disoriented afterward and stumbled as he tried to get to his feet.

Tagovailoa was immediately taken to the locker room and taken through the NFL’s concussion protocol, after which he was cleared. He returned to the game to start the third quarter, drawing criticism from viewers about why he was allowed to return to the game.

The NFLPA later announced that it was launching an investigation into the situation. The union later fired the Unaffiliated Neurotrauma Consultant who handled Tagovailoa’s injury during the game.

Jeff Miller, the NFL’s executive vice president overseeing health and safety, said in a virtual news conference Saturday that he believes this is the first time a UNC has been fired, and that the NFL did not support the decision to fire him.

The NFL and NFLPA said they reviewed video, jointly interviewed members of the Dolphins’ medical staff, the head athletic trainer, the Booth ATC Spotter, the UNC and Tagovailoa.

They found that Tagovailoa did not show any signs or symptoms of a concussion during his locker room exam, during the rest of the game, or throughout the following week. But immediately after he took the hit from Milano, gross motor instability was present.

After the game, Tagovailoa and Dolphins coach Mike McDaniel said the quarterback had suffered a back injury a few plays earlier on a quarterback sneak.

The review said that Tagovailoa told the medical staff that he aggravated his back injury on the play in question and that his back injury caused him to stumble.

It also said that the medical staff determined that the gross motor instability was not due to a concussion.

“They concluded the player’s back injury was the cause of his observed instability,” the parties said in the release. “However, the team physician and UNC 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.”

Commissioner Roger Goodell said at a fan forum in London on Saturday that the NFL will make a “change or two” to its concussion protocol as it has fielded criticism in the handling of Tagovailoa’s injury.

Less than a week after the injury, Tagovailoa started against the Cincinnati Bengals in a Thursday night game. He suffered a concussion in the first quarter after taking a hard sack, and displayed the fencing response after the scary hit. He was stretchered off the field and immediately taken to the hospital. He remains in the concussion protocol and will miss Sunday’s game against the Jets.

“The Protocol exists to establish a high standard of concussion care for each player,” the league and union said, “whereby every medical professional engages in a meaningful and rigorous examination of the player-patent. To that end, the parties remain committed to continuing to evaluate our Protocol to ensure it reflects the intended conservative appr