People have suggested going to a 6-man starting rotation and I've usually said it was ridiculous because it would be taking 5 starts a year from each of the top 5 and giving it to a far lesser starter.
But I've been giving some thought to a modified 6-man rotation. The top 3 pitchers pitch in their turn no matter what. The next few starters are basically a group of mediocre interchangeable parts.
So here's what I'm thinking. Let's say your opponent on the day the #4 guy starts is Atlanta, and your #6 guy has a history of shutting them down. Pitch the #6 guy against Atlanta! Then if the next day they're playing Philadelphia and your #4 guy has a history of shutting down Philly, use him! Let the #5 guy spend a turn in the bullpen.
Of course, this will only work if Collins sets the rotation about 2 weeks in advance so the pitchers can properly prepare themselves.
I welcome any thoughts.