It is a position that Troy Douglas, North Carolina's defensive backs coach, thinks about a lot.
The Tar Heels have used a safety in that position over the last several years. That is not by preference, but by necessity.
"Coach Withers and I would probably rather use a corner in the nickel spot, because of the man situation where you are going to put the nickel on the slot receiver," Douglas said. "You are not going to get as much physical play, run support and blitzing with a corner, but when you go to a nickel defense, you're matching skill on skill, which means you ought to put your best skill guy out there. We haven't had that luxury, because the safety position has been a little more developed than the corner position has been."
"The problem is that a lot of times you're playing man coverage, and you put in another corner and just sub him, they know you're going to play man coverage," Douglas continued.
"So the guy who plays nickel has to have a little savvy, he's got to know zone concepts, what his drops are, you've got to be able to teach him. The safeties have a little bit better understanding of that than the corners do. You've got to get a smart corner that's physical enough to handle it. We've used safeties at the nickel spot, but in a perfect world, you'd use a corner as your nickel back."
A nickel back can be a starter at another secondary position. Kendric Burney played nickel at times, with Jordan Hemby taking his position on the corner. DaNorris Searcy could play nickel, but he already had enough to deal with.
"Because DaNorris was returning punts, and he was a first year starter, we didn't want to put too much on his plate (by making him the nickel back)," Douglas said. "When Matt (Merletti) went out, a couple of games we tried to move Melvin (Williams) and tried to make him a nickel.
"As of right now (Searcy) is the punt returner and kick returner - by the end of (last) season he was returning kicks, too. All the special teams play, it is a lot to put on a guy"
With Merletti back, Douglas hopes that situation is resolved.
"If Merletti had stayed healthy last year, I thought he would be the nickel (back)," Douglas said.
"If the stars align, if Merletti can stay healthy, hopefully he can be the nickel, you can leave Gene (Robinson) as a second nickel, or backup safety, and go from there – and DaNorris can stay in one spot instead of having him play two spots."
With the experience coming back in the secondary, Douglas seems convinced that while they don't know where everyone will fit right now, they won't lack for applicants for the nickel back.
"That's one good thing about our kids is that they are older, they know the system, they've been in the system a long time," Douglas said. "It is kind of interchangeable, because Charlie (Brown) has played in there, KB has played in there, DaNorris has played in there, Merletti has played in there, and Gene has played a few snaps in there - I am talking about the nickel on the slot. So you've got a number of bodies, it is just a matter of figuring out what we're going to do."
Following the nickel back position, and who will man it, will be one of the stories to watch this spring.