I've linked the play below. Now I thought a player was down when they gave up any attempt to advance the ball. That came up in a NFL game a few weeks ago, a player caught the pass and went to the ground then got up and was hit and fumbled and the ruling was that even though the player wasn't down because the player wasn't trying to advance the ball the play was over. However, the link below shows a player catching a kick in the endzone and making no attempt to advance the ball yet the fumble was allowed to stand. Do they have to go to the ground and then when they get up not try to advance the ball?
Now if the ball wasn't down then could the defensive players not have just lit him up, gone high and low at full tilt for the tackle and it wouldn't have been unnecary roughness?