The challenge coaches face is replacing players they were counting on to be major pieces of a puzzle. In a lot of cases, there is just no way to make the necessary adjustments.
You know, I looked at my face in the mirror this morning, and I like being old. My face has more content and when I train in the gym now, I am not training to be strong or handsome - just better than I was yesterday. These days the race is just against myself.