The NFL and NFL Players Association have agreed to modify concussion protocols following an investigation of Tua Tagovailoa's recent injury, saying his return to a game against the Buffalo Bills was "not what was intended when the protocols were drafted".
Although the investigation found the Miami Dolphins to have followed existing protocols "as written", NFLPA president J.C. Tretter believes Tagovailoa's treatment was not a "meaningful application" of the rules.
The Dolphins came under heavy scrutiny for their decision to field Tagovailoa against the Cincinnati Bengals in Week 4, a game in which he sustained a concussion.
In Tagovailoa's previous outing against the Bills, he appeared unsteady on his feet after his head slammed against the turf following a heavy collision.
The NFL and NFLPA launched an investigation into the handling of that injury after he returned to the field shortly thereafter, with head coach Mike McDaniel saying he suffered a back injury.
A joint NFL-NFLPA statement released on Saturday read: "The parties have completed their joint review of the application of the NFL's concussion protocol following the injury to Miami Dolphins Quarterback Tua Tagovailoa during their game on September 25, 2022.
"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.
"As such, as has been done in previous cases, based on the advice of the parties' respective medical experts, the protocol will be modified to enhance the safety of the players.
"Specifically, the term 'ataxia' has been added to the mandatory 'no-go' symptoms. If a player is diagnosed with 'ataxia' by any club or neutral physician involved in the application of the concussion protocol, he will be prohibited from returning to the game.
"The parties remain committed to continuing to evaluate our protocol to ensure it reflects the intended conservative approach to evaluating player-patients for potential head injuries."
Tretter, however, has since taken to social media to criticise the Dolphins' handling of the incident, tweeting: "We do not believe this was a meaningful application of the protocols.
"Nobody, including the NFL, believes he should have been put back in the game. It is problematic that he was cleared for a back injury for which the lead doctors never took the time to examine."
Tagovailoa has been ruled out of the Dolphins' Week 5 fixture against the New York Jets on Sunday.