Farrior - He no longer offers consistency in the middle. While he was a pleasant surprise last year, his play has declined substantially and he is no longer an asset.
Hampton - A 34 NT plugs gaps and this one doesn't. He has been a surprise the last few seasons, but it seems like age has finally caught up with him.
McFadden - Always hurt, never plays and when he does, he is average, at best. Wasted cap room right now and a shame considering how well he played prior to going to Arizona.
Smith - He simply isn't the end that he once was. Unfortunately, I think the injuries have prevented him from maintaining his strength and he no longer is capable of his old style of play. If your end doesn't occupy blocks or chip in on the run game, he needs to improve or be replaced. At Smith's age, I think it's the latter, unfortunately.
Colon - He is a mediocre tackle to begin with and now always hurt. With such a significant cap hit, I'd rather see the Steelers try to trade him away to a team like Chicago (if they are still interested) and call it a day.