The NFL season is a 16-game grind that can wear down the strongest stone, and players who were barely sniffing the game-day roster in Week 1 could suddenly find themselves in prominent roles by Week 8, if not Week 2 or 3. The deeper your league, the fewer obvious sleepers and high-upside rookies will be available to fill up those reserve spots, and you might have to look much further into the player pool to find assets with potential to help throughout the season.

There are a few things to look for in a roster-worthy backup. First, is the backup's skill set suitable for a larger role? Particularly at running back, the No. 2 guy on the depth chart isn't necessarily the player who will become No. 1 if the starter gets hurt. The backup is often a passing-down specialist, in which case the third-stringer might be next in line to serve as the lead runner.

Wide receiver also has its own version of specialization — lining up in the slot requires a different skills profile than playing on the outside in some offenses, and a team's possession receiver is not going to become a downfield threat just because the usual speed merchant is nursing a sore hamstring. Rushing attempts and targets are important, but a player needs to be able to do something with them, or the offensive coordinator will start calling a different number.

Second, how likely is the backup to get a chance at a larger role?