Ambidextrous pitchers and default rules

The Oakland A's have called up pitcher Pat Venditte, who is genuinely ambidextrous and a MLB-quality pitcher with both hands. He pitched against Boston at Fenway on Friday evening, getting outs with both arms in the Seventh. More interesting, Venditte raises the prospect of a switch-pitcher facing a switch-hitter in the Majors. In July 2008, Venditte, then pitching for the Staten Island Yankees, got into a lengthy back-and-forth, with Venditte switching hands and the batter switching sides of the plate (video below).

The Professional Baseball Umpires Corporation soon after announced a new rule to address the situation: The pitcher must indicate which arm he will throw with (usually by stepping onto the rubber with his glove on a given hand), after which the batter can choose which side of the plate to hit from. After throwing one pitch, the pitcher and batter can each change once during an at-bat.

This is a fun example of default rules in action. Someone has to be the first mover in these situations, with the reacting player having the benefit of being the second mover. Needing to get the game moving, the umpires resolved that 2008 situation by making the batter choose a side first and allowing Venditte to respond.

But the subsequently codified rule goes the other way, giving the batter the initial advantage by making the pitcher declare a side first, allowing the batter to select the advantageous response. The logic was that the pitcher always goes first--we always know which hand the pitcher throws with (since every other pitcher throws with only one hand) and the batting team can seek an advantage against that (in selecting a pinch-hitter or in deciding which side a switch-hitter will hit from). Essentially, the rule forces Venditte to choose whether to "be" a righty or lefty at the outset of each at-bat, eliminating the uniqueness of the switch-pitcher.