'John Murphy: I consider Marcell Dareus the most indispensable man on the Bills roster. If he can get back to his form of 2013-14, the Buffalo defense should also return to prominence. So far this offseason, Marcell has shown that he’s matured and more serious about his craft than he has appeared to be the last two seasons. He seems focused and has worked hard to get in good condition during his regular appearances at the voluntary workouts.'