If F1, a left-handed pitcher, lifts his nonpivot foot and throws to F3, what is the ruling?

In this scenario, the ruling focuses on the specific actions of the pitcher when making a throw to a base while in the set position. When a left-handed pitcher, like F1, lifts his nonpivot foot to throw to F3, it is critical to determine whether he has properly disengaged from the pitching plate before making that throw.

If F1 has not previously stepped off the plate, then lifting the nonpivot foot and throwing constitutes a balk. This is because the rules require a pitcher to have legally disengaged from the pitching plate (stepping off) before making a throw to a base. The intention of this rule is to prevent deceptive movements that could lead to an unfair advantage for the pitcher.

In contrast, if the pitcher had stepped off before lifting his nonpivot foot, the act of throwing to a base would then be legal. However, the context of not having stepped off the plate makes the action a balk, ensuring fair play and discouraging any confusing or deceptive pitching maneuvers. Thus, this choice is correct, as it aligns with the rules governing pitching actions in baseball.