LEGAL DISCLAIMER: If you have written or discussed hidden value being a key to making an NFL roster at any point in any context recently on your news source, website, or blog, this post is purely coincidental and not an attempt to steal your material.
Entering training camp, all 32 teams have players who are unproven and just hoping to latch on and make the roster any way they can. You probably didn't need me to tell you that. I think when evaluating these players, sometimes people put emphasis on the wrong things, though.
The guy who posts 9 catches for 100 yards in a preseason game has clearly had a good night and taken a step to making his team's roster. Is this necessarily the most important thing if his team is set at the position, and his only way to making the roster is as the fifth receiver? Perhaps not. This guy's playing time is likely to be limited, and he will not be a featured part of his team's offense. What if this guy is an ace gunner on punt coverage units and is a quality return man? He will make much more of an impact in these roles so in an odd way they might be at least as important in a team's evaluation.
This is the kind of thing that makes it tough on a guy like David Nelson. I don't think Nelson is explosive enough to be a quality starter. He's NFL material, though. You could do a lot worse for a depth guy. The problem is he doesn't really add value anywhere else. If you had a guy with Nelson's receiving skills who was a special teams ace, you probably would have a player with decent value. Nelson might not make the roster if a younger guy he is up against can provide said value at another spot.
So as we head into camp just keep in mind that this is part of the process. Look deep. The backup guard who can also slide inside and play center will have a leg up. So will the fullback who has experience working as a featured ball carrier because somebody got hurt in college. These aren't the only considerations. Performing well at your primary position certainly matters. Sometimes I think we just forget the difference versatility and hidden value can make.