The Steelers are (as always) led by Ben Roethlisberger. Big Ben is not an easy target for defensive coordinators or defensive linemen and the the biggest issue with stopping him is his ability to elude would-be-tacklers. The Titans defensive linemen can't over pursue and need to get as many hats to the ball as they can.
Speaking of gang tackling lets talk about Isaac Redman. The Bowie State grad wasn't an issue on the ground for the Titans, the Titans couldn't tackle him after a catch to save their lives. Redman averaged 26.3(!) YPR last year which is staggering. The Titans need to do a better job taking Redman down on the first attempt, or it will be a long day for the defense.
Those two words go together like bacon and eggs, but this year the bacon is sort of burnt and the eggs look like they have been cooking for way to long. That clever (not really) metaphor is my way of describing the aging defense. The Steelers are in an area right now that no team wants to be in, they are aging but they don't have the talent to justify the older players starting. For example, the Steelers tried to upgrade from Jason Worlids by drafting Jarvis Jones. Unfortunately, Jones has been injured and ineffective so week one they will be rolling out Worilds.
Another factor to consider is the fear factor they lost when they didn't re-sign James Harrison. Polamalu is a good player, but it is his 11th year and he has only played one full season in the last four years. That doesn't exactly make a team that (for the most part) hasn't seen him, afraid of #43.
There are two individual matchups in this game that could be crucial, both involve interior linemen. The first is Chance Warmack vs the blitzer. I don't know who will be blitzing or how often they will come, but Chance Warmack's awareness will be crucial. Can he pound the defense in the running game? Almost undoubtedly. But the question is how will he deal with the exotic blitzes that just don't exist in college or preseason.
The second matchup is Jurrell Casey vs David Decastro and Mike Pouncey. The offensive line of the Steelers has looked pitiful the last...forever. In fact, one of the reasons why the Titans won last year's contest was because there was constant pressure on the QB for four quarters. From the last 6-10 games (including preseason) it looks like the edge would go to Casey in this matchup. The Titans will need him to be a space eater vs the run and a pocket pusher vs the QB, so if he has a good game it is a hard to see the Steelers winning this game.
My prediction: 31-17 Titans
The Steelers will get a TD from Big Ben's elusiveness causing a breakdown in coverage, and another likely later in the game when the Titans start to get comfortable. However, the Titans will just be too much for the older team. The running game is worth two TDs, and I believe that Locker will throw another two: one to a TE/FB and another to Nate Washington.