Analysts have already begun to write off the Steelers this year, before the draft even takes place. Michael Clayton is one of the few that I've heard say, "Never write off a team with Big Ben on it." And I definitely think that holds true.
The last two years our offensive line, secondary, WRs, and QB have all been banged up and knocked out of games. The turning point of last year from hopeful to hopeless was after Big Ben received that fluke injury against KC. Our O-line has been in injury purgatory these last 2 years with Colon going to IR and shuffling being almost constant. Our WRs have all missed games recently, most notably Brown last year and Sanders the year before. Wallace missed a fair amount of time with a tweaked hamstring.
Speaking of hamstrings, Woodley has been injured or below 100% for a large chunk of the last 2 years and Harrison has had an injured back. Polamalu has also been far below his usual explosive self, but he's hoping to remedy that this year. He has stated that he feels he may not have been in ideal shape due to not enough work outs during the offseason. So when did he start his workout this year? The week after the season ended for us.
The main point is, that without some of these key injuries (and injuries to many of the backups) these past two years could have gone very differently. If we can maintain a healthy O-line and keep Ben upright and in all 16 games, I think we have a very good shot in the playoffs. The draft has yet to happen, but the Steelers rarely get a player in the draft who has an impact year 1. A big possible addition would be Bradshaw who could immediately legitimize our running game (unless he falls to injury again).
I know that all teams are prone to injury and that's just part of football that teams need to deal with, but if we're able to keep those to a minimum, I definitely wouldn't count us out this year.