That doesn't make any sense. Let's take an extreme case: guy catches the ball going to the ground on his back as he enters the endzone; he's cradling the ball in his chest, but it moves as his back hits the ground. The ball, though moving, never leaves his chest, which is pointed up to the sky, until he finally secures it. If the ball never hits the ground and the player never goes out of bounds, it cannot not be a catch.