Obviously, daily fantasy sports is all about assembling lineups consisting of players most likely to produce the greatest amount of statistics. And in football, as is the case in just about any sport, production is a function of opportunity.
So it makes some sense to determine which players are on the field the most in order to have an opportunity to produce.
There are a number of sources for that information and among them is Football Outsiders, which provides sortable statistics by position in categories such as offensive snaps.