The protocol itself kicks into action when a player is either displaying or self-reporting signs of head injury. Once that happens, the team’s medical staff as well as the league’s unaffiliated neurotrauma consultants — three are assigned to each game — take further steps.

Patriots coach Mike Vrabel left his team’s 16-3 wild-card playoff victory over the Los Angeles Chargers with his face literally bloodied, but an unshaken confidence in his team.

Gonzalez sustained the injury during the fourth quarter of Sunday night's 16-3 wild-card win over the Los Angeles Chargers and did not return to the game.