In our O, it doesnt matter who the starting back is. You can start MI, CI or PT. I think SP liked having the Is starting over PT to see what the opposing D is doing and at the same time, keeping PT fresh to counter what they are doing (And BTW, CI did start 2 games late in the season over PT). Also, because neither CI or MI were pretty much 1or 2 down backs, they were better to start games as pure runners. And the Saints, with either I in the game on early downs, would give a heavy run look and go playaction from time to time.