The Pittsburgh Steelers were the most feared team in football during the 2000s—not just because of their talent, but because of their sheer physicality. When you have a wide receiver who was punishing people to the point that they had to create a rule to stop it, you know you’re setting a certain physical tone in your game.
But the NFL changed the tone of the game on them in 2011, indeed, in-season, with the sudden shift toward emphasizing certain rules regarding player safety, which in the intervening years led to more formal rule changes to better protect players.