what's the diff? The way managers work it today, they use so many guys they almost guarantee that they are going to bring in someone having an off-day.
I say that tongue in cheek but I do believe that the modern system completely misses the reality that on any given day, some guys are not going to be able to perform, and that the more guys you regularly use in one game, the more games you put at risk of hitting a guy who gets shelled and loses that game.
That goes under what I would call genneral over confidence in numbers. A player is NOT his stats. His stats are only the average of what he is over time. On any given day he might be anything other than what his stats say he should be. Ignore that at your peril as a manager.