Mendenhall tore his ACL in the final game and will be out for the playoffs. This injury definitely doesn't help Pittsburgh, and although Mendy may not have had the best year, 1082 total yards and 9 TDs, losing your starting runningback sucks. The carries now will be split between Isaac Redman and rookie John Clay. The Steelers already don't have an offensive line so anymore losses in protecting Big Ben is an awful thing.
Another bad thing for the Steelers is that they will be without their stud safety Ryan Clark who has sickle cell trait, a condition that can be problematic in the high altitude of Denver. In a 2007 game there, Clark became violently ill and lost his spleen and gall bladder because of deprivation of oxygen to his major organs. Luckily they are going against Tebow who only completes 5 passes a game. So lets just not hope they are top left.
Somehow I have to think the league is behind both of these things.