I always see this, and I'm really not sure how true it is. I was at the game and I know Polamalu, Ward, Randle El, Harrison, etc., all played the majority of the game. I've heard "Brian St. Pierre beat the Bills." St. Pierre threw maybe one pass in that game. I think Maddox started for Roethlisberger, but even he was a decent player.
I think Roethlisberger and Bettis were the only ones who sat.
Then again, I have an awful memory, so you could still be right.