The NFL announced Sunday that it will launch a review with the NFLPA over the handling of a hard helmet-to-helmet hit on Cam Newton in Thursday night's opener. The NFLPA announced it would seek a compliance investigation after our initial report that it was strongly considering doing so.

The NFL's new concussion-protocol enforcement agreement with the NFLPA was immediately tested on opening night and the NFLPA wants to know why Newton never received a cognitive exam on the sidelines despite suffering repeated blows to the head, and despite Newton appearing to clutch his head and have difficulty getting to his feet at times.

A source says the NFLPA has already conducted several interviews, but wants to talk to at least two more key figures involved in Thursday night's game.

Bus Cook, Newton's agent, said he supports the NFPLA investigation after watching Thursday night's game.

"It bothered me watching that game," said Cook's whose clients include Hall of Famer Brett Favre. "I've been through this before with Brett and the 'Bountygate' game (the NFC Championship between the Vikings and Saints) and I was having flashbacks to that. The ref's aren't going to be perfect, but this is more than one or two hits ... I'm glad the PA is stepping up and I think this can help the situation for everyone. If safety is the top priority, then you've got to do something now."

The NFL released a statement on Friday indicating that during a stop in play Thursday, the medical staff, along with the independent specialist, reviewed video of Newton after suffering the final blow to his head, concluding there was no evidence in their estimation that he required additional testing or needed to be removed from the game.

On Sunday morning, however, NFL spokesman Brian McCarthy issued a new statement, saying the league will review the matter again:

The NFL is committed to the proper application of the Concussion Protocol. In order to ensure that it is being uniformly applied across all 32 NFL teams, we have decided to initiate a review of the medical team's response to the Cam Newton tackle, under the procedure set forth by the collective bargaining agreement. Under that procedure, representatives from the league and the players association will review the relevant documents and video and interview the involved parties to ensure that the Protocol was applied properly. It is important to note that initiation of this process does not mean that we have seen any evidence that the Protocol was applied improperly, but simply reflects our obligation to ensure the health and safety of our players.

Under the new protocol, the NFLPA would have two weeks to inform the NFL that it wanted a situation investigated. If any wrongdoing is determined by the joint investigation, then clubs could now be subject to considerable discipline, such as steep fines and potential loss of draft picks.

This would be the first time the process is enacted.

The NFLPA was surprised by the league's Friday statement, a source said, since it was written without conducting any formal review with the union.

Should Cam have been removed from Thursday's game? USATSI

Under the protocol, the spotters in the press box -- also not affiliated with the teams -- can call down to stop the game so that a player may be removed to get examined. The league has gone to lengths to detail its attempts to make the game safer, but there was considerable public and media backlash to the beating Newton absorbed as well as pointed postgame remarks from some of his teammates and from the quarterback's father. Given the high profile of the game and the prominence of the player involved, the NFLPA is also under outside and internal pressure to exam the matter as fully as possible via the new investigative/enforcement system.

Newton was examined multiple times after the game and was not placed in the concussion protocol following those checks, though in some cases symptoms can take days to manifest themselves fully. Safety remains one of the biggest challenges facing the league, with in-game officials being urged to err on the side of caution when possible. Newton absorbed at least four direct shots to the head, at least two of which were clearly illegal, according to the league's internal review, though only one was penalized.

If, after a joint NFL/NFLPA investigation into the application of the concussion protocol the sides differ as to whether punishment is warranted, then a third-party arbitrator would make a final decision as to whether any punishment is handed out.