"The league said Tomlin's actions — he was standing on the white stripe that borders the playing field and took a step onto the field during Jacoby Jones' kickoff return — should have resulted in a 15-yard unsportsmanlike conduct penalty."
As we reported last week, Tomlin had said he wasn't paying attention to the field and was instead looking at the JumboTron when the interference occurred. You can see video of what happened here.
In a statement, Tomlin said: "As I stated yesterday, I take full responsibility for my actions, and I apologize for causing negative attention to the Pittsburgh Steelers organization.
"I accept the penalty that I received. I will no longer address this issue as I am preparing for an important game this Sunday against the Miami Dolphins," he said.
The fine imposed on Tomlin is the second-largest for an NFL coach, ESPN says.