He will almost certainly be suspended for his terrifying actions against the Penguins' Brooks Orpik.
During a stoppage in play, Thornton skated nearly the length of the ice, jumped Orpik, slew-footed him to the ice and punched him twice in the head at 11:06 of the first period. Thornton was given a match penalty.
Orpik was taken off the ice on a stretcher and transported to Massachusetts General Hospital, where he was diagnosed with a concussion. He returned to TD Garden and was cleared to travel with the team back to Pittsburgh.
After the game, Thornton was informed of his disciplinary hearing with the league, so he did not travel to Toronto with the team. He understands he will likely be suspended and fined for the incident.
In the Bruins' locker room after the dramatic come-from-behind victory, Thornton was distraught over his actions. He was soft-spoken and nearly broke down, realizing his on-ice behavior in this matter was uncalled for.
"Obviously, I made a mistake. I'm aware of it. I've been told they're having a hearing and it's hard for me to say much more than that. It was not my intention. I feel awful. I felt sick all game," Thornton said.
Thornton's role is to be an enforcer, but he has never been suspended during his NHL career. He's an old-school type of player who defends his teammates when needed. Before Saturday's incident, he had never crossed the line. He has fought opponents who have crossed the line, and he suffered a concussion when fighting the Buffalo Sabres' John Scott a season ago.
Here's what Thornton told ESPNNewYork.com's Katie Strang during a recent interview when asked whether or not the code of fighting still exists:
"I take a lot of pride in that. I do. People could probably criticize that I'm a little too honorable, I suppose, in some instances. I've been a firm believer my whole life that what goes around comes around. If you're one of those guys that suckers someone when they're down or you go after somebody that doesn't deserve it or isn't the same category as you, that will come back and bite you at some point, too. I also take a lot of pride in the fact that I can play 8-12 minutes a night. I've had to work extremely hard on that part of my game to bring more to the table than just fighting. That's part of my game, but I can do a lot more."
His presence in the lineup makes a difference for the Bruins. His actions against Orpik did not involve a fight. Thornton attempted to get Orpik to drop the gloves after his hit on the Bruins' Loui Eriksson resulted in a concussion, but Orpik would not oblige. If he had, it's likely the ill will would have ended there, before Thornton took things too far.
Later in the period, Thornton did what he did.
In the locker room afterward, he was genuinely almost in tears.
"It's always my job, I guess, to defend my teammates," Thornton said. "But I prided myself for a long time to stay within the lines. It's hard for me to talk about right now. I can't say 'I'm sorry' enough. I'm sure I'll be criticized for saying it, but it's true and I hope he's doing all right. I heard that he's conscious and talking, and I'm happy for that."
During a recent interview with ESPNBoston.com, Bruins president Cam Neely was also asked about the subject of fighting. He said he believes there's a place for it in the NHL, but he's not in favor of staged fighting or retaliation for a clean hit.
"Listen, I don't believe in staged fights, I don't like them, never have. I don't believe in a fight resulting because of a good, hard, clean bodycheck. You see that a lot and I don't understand that either. I can understand if somebody hits somebody in a position they shouldn't, but when it's a good, clean, hard bodycheck, there shouldn't be a need to come over and protect your teammate. The player that gets hit should take the number, like the old days, just take the number of the truck that just hit you. I still believe there are things that happen on the ice that you want the other player to be held accountable. Two minutes in the box, and I've heard some people say, 'Well, a good, clean, hard bodycheck will do the number.' Well, it won't do the number.
"I still believe there's a place in our game for it. I think it's a skill set that there are players out there that can play, but also have that intimidation factor that if they get pissed off and drop their gloves, it's going to make an impact on the game."
From an injury standpoint, it has been a difficult stretch for the Bruins. Not only did they lose Eriksson to a concussion, his second in a five-week span, they also saw Johnny Boychuk taken off the ice on a stretcher during Thursday's 2-1 loss to the Montreal Canadiens at Bell Centre in Montreal.
Seeing Eriksson having trouble getting to his feet and barely making it to the bench after the Orpik hit, the Bruins became an emotional team. Thornton was caught in the heat of the moment and did something he'll regret for a long time.