[tibear]

OK, now I'm a confused.

I've always been told that a defender has the priority when playing a ball coming directly off a bat, however, if a defensive player had a clear chance to make a play on the ball and bobbles the ball, the defense is no longer playing a batted ball but a loose ball and must now ensure they do not obstruct a runner from advancing.

Now you seem to imply that a missed opportunity by the defense to make a play on a batted ball has no bearing on whether a subsequent play on the same ball can be ruled interference.