First of all, can we get people once and for all to spell "Nickel" correctly? It's only one of the most common words in the American lexicon. Are there other countries where people can't spell their own money correctly? I doubt it somehow.
Second, the nickel just means the fifth defensive back. Five cents, five DBs, hence the term. A nickel back can be anywhere on the field, he can line up as a safety or as corner, it doesn't matter, the terminology is basically irrelevant. Troy as a corner usually does line up inside, but a DB who covers a receiver in the slot is also called a cornerback. On the Patriots you'll often see the team bring in a safety in the nickel and move Wilson to play the third corner position in the slot. Then again sometimes the nickel is a corner (in Samuel's rookie year he was often the nickel, playing the inside slot corner position, which the Pats call the "Star" position). So the term nickel back is basically meaningless.
I think what you're probably trying to say is that Troy never plays on the outside, which is more or less true, although he does line up out there occasionally. Beyond that he's obviously not going to step in and be a starter. But to say that the nickel back is not going to replace Scott is kind of silly, because the likelihood is that your fifth DB is going to be the replacement when one of the first four goes down to injury.
