Battting

[Robert Goodman]

In Fed it's illegal batting because the ball has touched the ground ("The ball rolls"), and it's not a loose ball foul because the fumble was from beyond A's line. Enforcement would be half the distance from the end of the run (where the fumble occurred).

There's no such thing as "new force" in determining who put the ball out of bounds, so if A declined the penalty, the spot of forward progress would be where the fumble occurred, and they wouldn't get the extra distance of the fumble and bat.