Hjalmarsson was suspended two games by the NHL for his hard hit on Buffalo Sabres winger Jason Pominville in Monday's game. Pominville suffered a concussion.
"There's nothing I can do about that now," Hjalmarsson said. "The league gave me two games, and I just have to accept that.
"They have a tough job to say how many games I'm going to get. It's a fast game out there and you got to make decisions real fast. Sometimes it can get ugly, even if I didn't really intend to hurt him. I really hope Jason gets well as soon as possible."
The Sabres made some strong statements regarding the hit on Tuesday. Goalie Ryan Miller called it a "dumb hockey play" and had hoped the league would set a precedent by taking serious action.
"It's the league's decisions, not the other team's," Hjalmarsson said. "That's their opinion. It's only the league's opinion that matters. ... If I could turn back time, I probably would have acted different."
The NHL told Hjalmarsson to consider the situation that the opposing player is in when making a hit.
"It was too hard of a hit, I guess," Hjalmarsson said. "I should have considered him being in a vulnerable position a bit more and not hit him as hard. That's what they said."
The NHL's official announcement, which came out Wednesday before the Hawks host the Predators, said Hjalmarsson "will forfeit $37,634.40 in salary for delivering a hit from behind that caused injury to Jason Pominville of the Buffalo Sabres."
Hjalmarsson will sit out Wednesday against the Predators and Friday's game in Columbus against the Blue Jackets.