With LOLB LaMarr Woodley out with a hamstring injury, Harrison's return couldn't have come at a better time. The Steelers need stout run support and pass rush to counter a talented and multi-faceted Ravens offense.
Harrison will also help a defense lacking in the turnover department this season. He leads the league in forced fumbles over the past five seasons, and will hit with the ferocity that's earned him that statistic.
The Ravens will get a return of their own, in the form of LG Ben Grubbs, who hasn't played the last few weeks either. He'll replace Andre Gurode, who's better suited to play center, and showed it the last few games.
It's approximiately one hour to kickoff in the game's best rivalry. It's time to get into whatever pregame tradition you have and get ready for a classic football game.