Understanding Force

[ABoselli]

What if its slowly rolling parallel to the goalline with no chance of making it to the endzone?

I'm all for interpreting rules. If it's bounding back towards A's goal and just as lumbering B79 bends over to try and secure it, it bounces into him, I'm ruling no new force. If 4 players all dive for it and it goes into A's endzone, I'm still going with the original force. But if it's clearly moving away from the goalline, even slightly, or rolling parallel, and B muffs it into A's end zone, that's a TB if A recovers or it becomes dead behind that goalline.