Greg A. Harris was a pitcher with the Padres and Expos in the late '80s - early '90s. He is one of the most important players in the history of baseball. Never heard of him? I don't blame you. So why is he important?

Here's why: There is a rule in the rule book because of him.

You see, in a game in 1995, Harris became the first pitcher in modern history to switch pitch, that is, pitch with both arms in the same game. He had a special glove made with a thumb pocket on each side so he could change arms without having to go to the dugout for another glove. He worked on it for several years, but only ever switch pitched in one game.

Why is this important? Becasue rumor has it that the Oakland A's are about to call up Pat Venditte, who is a switch pitcher and a student of Harris. And unlike Harris, who only hit on the idea after he had been in the majors for several years, Venditte has been switch pitching since he was an amateur. It appears he will become the first pitcher in the history of the game to switch pitch on a regular basis.

So let's review Rule 8.01(f), aka the Greg Harris Rule: "A pitcher must indicate visually to the umpire-in-chief, the batter and any runners the hand with which he intends to pitch, which may be done by wearing his glove on the other hand while touching the pitcher's plate. The pitcher is not permitted to pitch with the other hand until the batter is retired, the batter becomes a runner, the inning ends, the batter is substituted for by a pinch-hitter or the pitcher incurs an injury. In the event a pitcher switches pitching hands during an at-bat because he has suffered an injury, the pitcher may not, for the remainder of the game, pitch with the hand from which he has switched. The pitcher shall not be given the opportunity to throw any preparatory pitches after switching pitching hands. Any change of pitching hands must be indicated clearly to the umpire-in-chief."

The upshot is: Venditte can choose to pitch to a hitter with either arm when the hitter comes up. He does this prior to throwing a pitch, usually by wearing his glove on the non-pitching hand. Once he chooses, he cannot switch until that at-bat ends, unless a pinch hitter comes in, or a few other circumstances occur.

I'm going to be curious to see how this works out. I don't see it ever becoming a widespread trend, but if it works, I can see some other pitchers trying it out to see if they can gain an advantage.