So I'm watching the Bears vs. Cowboys game and I saw the challenge by the Bears when the Cowboys running back, or somebody, appeared to have fumbled the ball. I know that these are two different plays but I still think there is some commonality in them.

I'm referring to the Calvin Johnson play last week. He caught the ball, his two feet touched the ground. He then had the ball in his right hand. Then his knees hit the ground. Then his butt. Then his left hand. Then the hand with the ball touched and the ball popped out from the force. If he didn't have control of the ball then that would have been seen when he first held the ball in one hand. He had a grip on that ball otherwise it would have dropped out.

Now for the play with the Cowboys. The player shoulder touches the ground and then the ball comes out right after.

So for one play we have:

Feet, legs/knees, butt, lower back, left arm and then the hand w/ ball hits ground, ball pops out.

Shoulder hits ground and ball comes out right after.

Yet the second play is called dead right when the shoulder touches but when many body parts touch for Johnson's play it is still active; as if the play would end only when his right hand touched the ground.

What is up with this?