Block.
If you think the player didn't get the ball yet, that means that the defender is guarding a moving player without the ball. As such, the defender must obtain LGP with time and distance for the opponent to stop or change direction....1-2 steps. Even if she got there just before contact, that, by rule, is too late.
Even if she had the ball, I still think it is a block. I don't think she stopped moving forward at all before contact.
On top of all of that, the contact was mostly with the defender's extended knee and arm.