The NFL has sent a memo to every team decreeing that if a concussion is even suspected, a player is to be removed from the field.
The league reminded teams that a player should never play after suffering such an injury. The memo also explains that if a medical staff believes a player may have suffered a concussion but he has not been diagnosed, he should be taken out of the game.
The memo includes a heading that reads, "WHEN IN DOUBT LEAVE THEM OUT," advising that teams should "always err on the side of caution."
Also included is a reiteration of the "Madden Rule," which states that a player removed from a game with a concussion must be escortedto the locker room and observed for a potential need of immediate hospitalization, and that, under no circumstances, may he return to the field.
From ProFootballTalk:
We'll surely see situations in which players think they're OK to play and say they don't want to be escorted to the locker room. The NFL is telling medical staffs that they have the authority to order a player to the locker room whether he wants to go or not.