Pittsburgh Penguins center Sidney Crosby (87) keeps the puck away from Boston Bruins defenseman Zdeno Chara (33) during the first period of their NHL clash in Boston on Saturday. Boston won 3-2. Greg M. Cooper / USA TODAY Sports

The Boston Bruins' last-minute win over the Pittsburgh Penguins on Saturday was overshadowed by Shawn Thornton's takedown of Penguins defenseman Brooks Orpik.

Zdeno Chara scored with 13 seconds left in regulation after David Krejci tied it late, lifting the Bruins to a 3-2 win in a game that saw Orpik taken from the ice on a stretcher.

Midway through the opening period, Thornton was given a match penalty for grabbing Orpik from behind, pulling him to the ice and punching him when he was down. Orpik appeared to be dazed by a punch, but may have also hit his head on the ice.

The Penguins said on their Twitter site that Orpik returned from Massachusetts General Hospital and will be traveling with the team back to Pittsburgh, according to Penguins coach Dan Bylsma.

"Obviously I made a mistake," Thornton said. "I'm aware of it. I've been told that they are having a hearing and it is hard for me to say much more other than that was not my intention. I feel awful. I feel sick."

Thornton, known as the Bruins' enforcer, knows he went over the line that comes with his role.

"It's always my job, I guess, to defend my teammates, but I've prided myself for a long time to stay within the lines," he said, speaking very quietly in the dressing room.

"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, but it's true."

Reilly Smith also scored for the Bruins, who haven't lost in regulation at home since late October (10-0-2).

Tuukka Rask stopped 28 shots for Boston.

Bruins coach Claude Julien said both teams should take some blame for physical play that went over the line at times.

"The only thing I'm going to say is it's not just one way here," he said. "There's a lot of blame to go around. We can all learn from it."