If the pitcher's non-pivot foot is on or behind a line extending through the front edge of the pitcher's plate:

• A. He is in the wind-up position.
• B. He is in the set position.
• C. He is in the wind-up and set positions simultaneously.
• D. Neither A nor B; it is always illegal for a pitcher to turn his shoulders to check a runner.

Answer: (A)

Focus on where the non-pivot foot sits in relation to the front edge line of the pitching plate. That line marks the boundary between the wind-up and the set position. If the non-pivot foot is on or behind that line, the pitcher is considered to be in the wind-up. If it were forward of that line, the pitcher would be in the set position.

So, with the non-pivot foot on or behind the line, the pitcher is in the wind-up position. The other options don’t fit because the set position involves the feet positioned forward of that line (a more compact stance), and the idea of being in both simultaneously or of turning shoulders to check a runner isn’t what defines these stances.