More times than not; when a ball carrier hits the ground and then fumbles, the ground is the cause. There may be exceptions, but you have to stay true to a rule no matter what. The refferee cant say, "The player's knee hit the ground prior to the ball coming lose. However, it is my opinion that the hit made simultaneousely might also have been the factor. Thereforer, it is a fumble."

I dont think thats gonna happen.