Doctor Who Evaluated Dolphins' Tua Tagovailoa Has Been Fired

The doctor involved in clearing Tua Tagovailoa after the Miami Dolphins' Sept. 25 game against the Buffalo Bills has been fired, league sources confirm to PEOPLE.

ESPN and the NFL Network first reported that the NFL Player's Association (NFLPA) has fired the doctor, an unaffiliated neurotrauma consultant, after they were found to have made "several mistakes" in their evaluation of Tagovailoa.

On Monday, a league source confirmed to PEOPLE that the NFLPA exercised its right to fire the doctor.

The Dolphins quarterback had left the game after hitting the back of his head on the ground and noticeably stumbling on the field. He was cleared to return to the game after passing his evaluation and the team stated that he had a back injury, rather than a head injury.

Five days later, Tagovailoa started in the Dolphins' Thursday night game against the Cincinnati Bengals and was sacked in the second quarter, again hitting his head into the ground. The QB was spotted holding up his hands with his fingers frozen in place, which Dr. Ann McKee, a neuropathologist and director of Boston University's CTE Center, tells PEOPLE is "a clear sign of a brain injury with brainstem dysfunction."

David Santiago/Miami Herald/Tribune News Service via Getty

The NFL and its player's union issued a statement Saturday that said Tagovailoa's return to last Sunday's game is still being reviewed. The organizations also said that they are reviewing their concussion protocols.

"The NFL and the NFLPA agree that The NFLPA's Mackey-White Health & Safety Committee and the NFL's Head Neck and Spine Committee have already begun conversations around the use of the term 'Gross Motor Instability' and we anticipate changes to the protocol being made in the coming days based on what has been learned thus far in the review process," the statement read.

Both the NFLPA and the NFL individually have the right to fire an unaffiliated neurotrauma consultant without agreement from the other organization, ESPN shared.

Jeff Moreland/Icon Sportswire via Getty Tua Tagovailoa

Tagovailoa was first listed by the Dolphins as questionable to return with a head injury on Sept. 25, but the team later said that a back injury caused him to sway, and he returned. In the second quarter of the Bengals game just days later, the sack by Josh Tapou saw medical professionals rush on the field as he was motionless for about 10 minutes afterward.

RELATED: Tua Tagovailoa Shouldn't Play the Rest of the Season After 2 Head Injuries, Concussion Expert Says

Before halftime, the team shared that Tua was conscious and had "movement in all his extremities" at the hospital. He was later discharged from the University of Cincinnati Medical Center. The QB then shared an update with fans on Twitter Friday evening.

"I want to thank everyone for all of their prayers and support since the game last night," Tagovailoa wrote. "It was difficult to not be able to finish the game and be there with my teammates, but I am grateful for the support and care I received from the Dolphins, my friends and family, and all the people who have reached out. I'm feeling much better and focused on recovering so I can get back out on the field with my teammates."

Dr. Chris Nowinski, a neuroscientist and the CEO of the Concussion Legacy Foundation, told PEOPLE last week that Tagovailoa "showed five distinct signs of a concussion" when he was allowed to return to the game against the Bills.

RELATED: Miami Dolphins' Tua Tagovailoa Suffers Second Head Injury in a Week During Game Against Bengals

"First he grabbed his head when he hit the ground, which is usually a sign your head hurts," Nowinski said. "Then when he stood up he took two bad steps sideways and backwards because balance was clearly off. Then he shook his head side to side in a classic clearing up the cobwebs, meaning he had a visual disturbance. Then he fell to the ground in a very awkward way, and then when he stood up, the only reason didn't fall again is because his teammates held him up."

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As for what Nowinski called the "fencing response" at the Bengals game — or the moment when the player's fingers froze up — Nowinski says he could have "horrible repercussions from two concussions in four days." Because of this, he shouldn't play the rest of the season, the neuroscientist said.

"If he survives two concussions in four days, God bless him, but three concussions in a season, the odds that he has a life-changing symptoms just keep increasing," Nowinski says. "We all will watch and wait and hope that he's one of the lucky ones."