Cam Newton is examined by medical personnel during Sunday’s game at New Orleans. (Chuck Cook/USA Today Sports)

The NFL and NFL Players Association on Monday launched a joint formal investigation of the Carolina Panthers’ handling of the injury suffered by quarterback Cam Newton during Sunday’s loss at New Orleans in an NFC first-round playoff game.

The Panthers could be subject to discipline from Commissioner Roger Goodell if the league and union determine the team violated the NFL’s concussion protocols.

It is the third incident this season known to have been formally investigated by the league and union under the policy they developed through a 2016 agreement, although they informally review every concussion evaluation.

The Seattle Seahawks were fined $100,000 for violating the concussion protocols in an evaluation of quarterback Russell Wilson. The Houston Texans were not punished for their handling of a concussion suffered by quarterback Tom Savage, although the NFL and NFLPA concluded the outcome of the Savage evaluation was unacceptable.

After completing their investigation of the Savage case, the league and union announced changes to the procedures for identifying and dealing with concussions. One of those modifications came into play Sunday with Newton: The change requires any player who falls or stumbles after suffering a potential head injury to be taken to the locker room for a concussion evaluation. A sideline evaluation is not sufficient, under the modified rules.

Newton absorbed a hard hit on a fourth-quarter sack Sunday and had to be helped up from the Superdome turf. Newton made his way toward the sideline but dropped to his knees before getting there.

Newton was evaluated in the medical tent on the Panthers’ sideline. He returned after missing only one offensive play; the Panthers announced he had been evaluated for a concussion and cleared to play.

After the game, Newton and Coach Ron Rivera said Newton had been hit in the eye. Rivera said Newton had been told to drop to a knee to give backup quarterback Derek Anderson, who replaced Newton for that one play, time to warm up on the sideline. The issue, then, could be whether Newton fell on his way to the sideline or took a knee on orders from a member of the medical staff.

Goodell and other NFL officials have said the league’s concussion-related rules are designed to put return-to-play decisions in the hands of doctors and medical personnel, without any consideration given to competitive concerns. Given that stance, it’s not clear how the Panthers’ statements that they told Newton to take a knee, to give Anderson time to warm up, will be viewed.

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