[MNBlue]

Originally Posted by mbcrowder

Considering that the actual spots on the field played by the various positions (other than pitcher and catcher) are not defined - how in the world could this be enforced? What's the penalty? What if I move my CF into the infield (or my 2B out to the outfield) and use an unorthodox lineup for a batter for whatever reason?

Blue: Coach - you switched your 2B and SS without telling me.
Coach: That's where we put our SS - on the right side of the bag.

There is a small amount of common sense associate with the rule:

8-1-2 A defensive player is entitled to change to a different defensive position at any time. The plate umpire shall report the change to the official scorer, team scorekeepers, and to the opposing coaches and scorekeepers, before the next pitch.

EFFECT—Failure to report defensive changes renders the player unreported. (See Rule 8-3-3.)

A.R. 8-1-2: If the second baseman is located closer to first base than the first baseman who is playing in and away from the foul line for a slapper, they are not considered to have exchanged defensive positions. However, if the catcher and first baseman exchange positions, they are considered to be unreported substitutes if the umpire is not notified.