... and hockey cards.  Part of the fun of collecting cards was trading them with friends or flipping them in an attempt to win more cards.

But, I always had a few of my favorite cards that I kept back, never to trade or flip.  They were the "untradeables."

You can apply a similar concept to an NFL roster in an attempt to gauge the strength of that roster.

You know you really have something special in a a player when you absolutely would not trade that player for a single other player at his position in the league. Nada. Not one.

Most teams are lucky to have one or two players that warrant this type of consideration. The Pittsburgh Steelers have at least eight and a strong argument could be made for a co...

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