That's why, since the Eagles hired Kelly early in 2013, there's been so much attention paid to the changes and innovations he's implemented: the smoothies and the practice schedule and the sleep- and hydration-tracking and the like. That's why Kelly can confound those who insisted he had to have a mobile quarterback to run his offense by contouring the system to help pocket passer Nick Foles flourish. He's at his most flexible when it's time to call plays and adjust to the flow and circumstances of a particular game. He's at his most rigid when it comes to the rest of the week, to all the tiny measures of self-discipline and team building that prepare his players for Sundays.