[greymule]

OK, I see what you mean. In baseball there's a slight disengagement practically simultaneous with the release. The pivot foot comes off just after the other foot hits the ground. (Funny, even as a pitcher, I never considered exactly what was happening during the motion.) But the nature of the overhand delivery makes it virtually impossible to "crow hop," so a replant of the pivot foot isn't an issue.

But in FP, the disengagement occurs much earlier, when the pitcher's arm is beginning to descend behind her. At the time of release, the pivot foot is several feet in front of the rubber, and the umpire has to be watching for a replant. (I do a lot of ASA and NCAA, and it's not difficult to spot.) After a FP game, the "groove" on the mound is long and deep. There's no such groove after a baseball game.

Now assuming a baseball pitcher wanted to pitch underhand, would the FP motion be legal?

it must be clear to the BU that the pitcher does have both feet in contact with the pitcher's plate at the beginning of the pitching motion

You make some good points, VanStanza, but remember that in Fed, the pitchers don't have to have both feet in contact. (However, I hear Fed is considering getting the rule in line with ASA and NCAA.) But the pitchers I see don't start with the right heel in contact with the front of the rubber. They generally put the pivot foot squarely on the rubber so that they can push off with the entire foot. And NCAA requires that at least half the foot be on the top surface of the pitcher's plate, while ASA does not.