Straddling a pivot foot
 

A1 picks up her dribble near the 3-point line, facing away from the basket. As she pivots to pass, all her teammates are covered, and she is stretched on her pivot foot. The defender, seeing that the girl with the ball has few options, walks and straddles the girl's leg, almost to the knee, but makes no contact. (I hope this is clear; no photo available.)

When the offensive player tries to straighten up on her pivot foot, she makes contact with the defender. Is this a foul on the defense? Offense? Incidental contact?

Defensive foul, blocking or pushing, depending on how the contact comes about and whether there's any advantage gained by it.

This is probably a good thing.

Because...? Why would this not be LGP?

I'd actually be concerned for A1's knee more than anything...one wrong twist caused by bumping into B1 and there goes her season.

I know there's nothing we can do about that as officials but having torn an ACL before, I think about those kinds of things

Because A1 is still entitled to that spot and the space above her pivot foot, IMO.

I do not see anything about this situation that the defense is doing illegally. And tearing a knee should also not be out concern. It sounds to me like the offense player put themselves in a bad position and did not give much room to move. I see nothing that makes this illegal and if contact takes place I would have to judge based on the contact.

Peace

Does not the law of verticality remain here? Foul on D for invading the space that is rightful the offensive player's. (If I'm envisioning this right.) Wouldn't the same principle apply for a player with ball, crouching/cowering and suddenly standing tall?

That's what I'd have.

I personally think so, and agree with Snaqs. I've got a defensive foul or nothing.

Blocking foul
 

Offensive player with ball is entitled to space from feet to ceiling. I would say defensive blocking foul.

I'm in agreement with this and will likely call it a pushing foul on the defense.

Wouldn't you agree that the space above a player's feet is within his/her vertical plane? So if there's contact, it's because the defender violated the opponent's verticality?

I've got a blocking foul.