The NFL Players Association has agreed to changes to the concussion protocol and is urging the NFL to do the same before Sunday's games kick off.
"Our union has agreed to change the concussion protocols to protect players from returning to play in the case of any similar incident to what we saw on September 25," the NFLPA Board and Executive Committee said in a statement Friday. "We would like these changes to go into effect before this weekend's games to immediately protect the players and hope the NFL accepts the changes before then as well."
The NFL responded later Friday, saying changes are "likely" but did not commit to a timeline for when they would be implemented.
"As we have discussed with the NFLPA, we agree that changes to the joint NFL-NFLPA protocols are necessary to further enhance player safety," the NFL's statement read. "We have already spoken to members of the NFL Head, Neck and Spine Committee and the leadership of the Unaffiliated Neurotrauma Consultants and Independent Certified Athletic Trainers who serve as spotters to discuss these likely changes."
Tagovailoa hit the back of his head on the ground and stumbled while trying to return to the huddle after a play in the Dolphins' game against the Buffalo Bills on Sept. 25. He was immediately taken to the locker room with a head injury, the team announced at the time.
He passed the locker room evaluation, however, and returned to finish the game after halftime with both Tagovailoa and the Dolphins clarifying that his stumble was caused by a back injury he suffered earlier in the game.
Four days later, Tagovailoa was taken to a local hospital after his head hit the turf in a Week 4 game against the Cincinnati Bengals. He was diagnosed with a concussion and is ruled out for Sunday's game against the Minnesota Vikings.
The NFLPA initiated its right to request a review of the NFL's concussion protocol following Tagovailoa's quick return to the game and terminated the unaffiliated neurotrauma consultant who initially evaluated the quarterback during the Bills game.
The NFL and NFLPA have both said they are committed to altering the concussion protocol based on what both parties learned during the review.
ESPN's Marcel Louis-Jacques contributed to this report.