Whose Call at Third?

[Big Slick]

Originally Posted by EsqUmp

I don't know specifically what ASA says about the coverage, but I bet by the book it is the base umpire's call.

No, it doesn't. In the most recent ASA umpire manual, with a runner on first only (Fast Pitch), ground ball to the infield (p.258):
B - Let the ball take them (sic) to the play. They (sic) are responsible for any play at 1st or 2B and the last runner to 3B.

(and for comparison purposes, for the Plate umpire: " . . . responsible for any play on the lead runner at 3B . . " (my emphasis)

In the FED mechanics book, Runner on first base only (p.40):
PLATE: " . . move toward third base to cover the advancing runner."

Additionally, the FED manual has the 4 times BU makes a call at third base (p.39) (these were in the ASA manual years ago, but have been removed):
1. On the BR on a triple with no runners on base
2. On the last runner into third base
3. On a lone runner on fly ball advancement.
4. On any return throw from the plate area or a cut-off by a player.

Barring the redundancy and silliness of these (basically 1 happens on all triples, regardless of any other runners; 1 and 3 are each a subset of 2), there is no mention of "first throw" or "initial play." These terms (or variants) are mentioned for different starting configurations (i.e. runner on second).

And for completeness sake, the SUP two umpire mechanic (as found on Arbiter) for a runner on first, ball hit in the infield:
P - ". . . Take any play on R1 at third base and the plate."

B - "..Make any call on R1 at second base and the batter-runner at first, second and third base. . ."