Well, the Steelers lose Ben for some undetermined time and potentially Ryan Clark. Polamalu hasn't played in 4 or 5 weeks and Harrison is still working back into shape. Currently, as the playoff picture sits the Steelers are a wildcard team and are two games ahead of the 7th, 8th and 9th place teams and 2.5 games ahead of the 10th pace team.
Each of the teams that are out of the playoffs have 7 games to play except the 10th who has 6 games to play. If the Steelers can find 4 wins and get to 10-6 the other teams will have to go 6-1 except for the 10th place team who would have to go 6-0 to get to 10 wins. I have no idea how the tie-breakers would shake out, but right now the Steelers are sitting in a good position even with Ben injured. Hopefully, Ben's shoulder isn't horrible and that he will be able to go should the Steelers make the playoffs.
The teams on the outside looking in at the playoffs in order are Chargers (Broncos, Ravens, Steelers), Dolphins (Pats twice, 49ers), Bengals (Steelers, Ravens) and Titans (Texans, Colts and Packers). Each team has two potential losses in their final 6 or 7 games and the Bengals have the easiest schedule remaining IMO.
Now, where are the 4 wins coming from under the condition that Lefty has to play the final 7 games?
Best bets for three of the wins would be Browns (2) and Bengals, the fourth win might have to be the Chargers or Cowboys, hopefully, both are cooked by the time the Steelers play them.
This is the worst case scenario in which Ben doesn't play another regular season game this year.