I think injuries killed the Steelers this season. Yes, injuries are part of the game. No, not all injuries are created equal. When they disproportionately affect a team's best players, or when there are numerous injuries on one unit or at one position, then it becomes a problem.
Ben Roethlisberger, Troy Polamalu and James Harrison are the three "superstars" on the team, and all three missed multiple games due to injuries. They also tried playing through their injuries and were ineffective in the process. Polamalu and Harrison both missed significant time early in the season and failed to make an impact until the final month. Roethlisberger was injured mid-season and hasn't been the same since.
Several other impact players (Antonio Brown, Ryan Clark, Maurkice Pouncey, Ike Taylor, LaMarr Woodley) missed multiple games as well, and two (Heath Miller, Mike Wallace) missed one game. In fact, Brett Keisel and Lawrence Timmons were the only two impact players who were healthy for all 16 games.
To make matters worse, the RBs and LBs were depleted by injuries early in the season, the QBs mid-season, and the CBs and offensive linemen late in the season. When third- and fourth-string players get significant playing time, then there's a problem. At least Baron Batch, Kelvin Beachum, Josh Victorian and DeMarcus Van **** all got to experience something more than the pre-season. 
Last April, the Steelers drafted David DeCastro in the first round and Sean Spence in the third round, and both players impressed the coaches during the pre-season, but both ended up on IR before the regular season even started. At least DeCastro was recalled. Spence was not. And Mike Adams, their second-round draft pick, was injured after filling in for another offensive lineman who ended up on IR. Adams missed the last six games of the season himself.
So yeah, when all a team's superstars and most of its impact players miss extended periods of time, and different units of the team get wiped out at various times, and two of the top three rookies don't even make it to the regular season, then it really does begin to add up and negatively impact the performance of the team, and it can most certainly make the difference between 11-5 or 12-4 and 8-8. It's death by a thousand cuts.
If the Steelers have a good draft and avoid too many significant injuries to their best players next season, then they'll be back in the mix in 2013.
Last edited by DBR96A; 12-31-2012 at 04:39 PM.
"We're a game-plan offense, and we're going to try to tailor our strengths against their weaknesses."
-Todd Haley, current Steelers offensive coordinator
"We're not going to change what we do regardless of who our opponent is or who's injured."
-Bruce Arians, former Steelers offensive coordinator