(The Sports Xchange) - Carolina Panthers quarterback Cam Newton absorbed multiple hits to the head in the season-opening loss at Denver, and Broncos' players said in the aftermath of Thursday's game that hitting the reigning MVP was key to the game plan.

Newton's father, Cecil, said the family was "grossly disturbed" by the repeated shots to his son.

Now the NFL and NFL Players Association are investigating the response by medical personnel during the game.

One specific hit -- helmet-to-helmet contact initiated by Broncos safety Darian Stewart -- prompted the compliance investigation.

"The NFL is committed to the proper application of the concussion protocol," the league spokesman said in a statement.

"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," NFL spokesman Brian McCarthy said in a statement.

"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."

The NFL safety advisory committee panel meets once a month and will discuss at the upcoming meeting whether to consider adopting college targeting penalty rules, which carry automatic ejection and a one-game suspension.

(Editing by Andrew Both)