[Tru_in_Blu]

Good question.

If part of a batter's foot is outside a line of the batter's box (when there ARE lines), s/he is considered to be out of the box. If s/he swings and contacts the ball, the batter is out.

Leaving the batter's box seems to have a bit more leeway in regards to the batter contacting the batted ball. If a foot was completely down and outside of the batter's box when contacting the ball, that's an obvious out. But if the foot was still down in the batter's box, or elevated either within or outside the batter's box, I believe that's still legal.

I had a similar call a while back with a right-handed batter bunting. The ball went straight down and hit the plate and popped straight back up. After the bunt, the batter's left foot was completely out of the box and on the ground. Then contact occurred with the ball. Her back foot/leg were still in the batter's box, but I couldn't say if the back foot was off the ground at that point.

I "gave the batter the benefit of the doubt" and called a dead ball, and then foul ball. Offensive coach liked it, defensive coach didn't.