If you leave a spot blank on your depth chart, how does it effect your minutes and rotation as opposed to filling them all in?  For example instead of filling all 4 spots in, you leave the third one blank. I currently fill them all, but I have seen it suggested 3 or 4 times in the forums to leave the third spot blank. However I can't recall anyone ever explainging why they do it.
 
I would appreciate as many replies as possible. Thanks!