[AtlUmpSteve]

PU goes up the line to cover 3B because BU is now behind the play; BU is on the right field outfield side of 2nd when the ball is overthrown, and would be trailing the play, while PU can see the play at 3B develop and move up. BU would have coverage at 3B only if a wild pitch or passed ball kept PU pinned at HP; in that case, BU should "rim" with the runner making the turn, and read/listen for PU to call BU off. On this play, BU may be able to cut in, but would still be trailing, in most cases.

PU should start to the holding zone (rather than stand flat footed behind HP) once the catcher releases the throw, and PU has ended all responsibilities at HP (no batter interference). As the play turns to 3B, PU should ease down toward 3B, and cut inside in fair territory to make the call at 3B.

At some point, it becomes obvious that there is no play at 3B, and ball is now is left field foul territory. PU should drive off right foot, change direction back to HP, staying in fair territory (inside-out theory). Remembering that PU was perhaps 10' short of 3B, and that ideal calling position is perhaps 10' short of HP, PU has significantly less travel than runner.

ASA does not recommend BU covering HP in this situation; same as U1 does not rotate to cover HP when counter-rotated to the B slot in 3 umpire system. Cutting across the full diamond from outfield side of 2B to HP is not desirable; the sole exception may be if PU goes down. Otherwise PU should effectively cover both 3B and HP.