Looked like an adjustment to a slightly slower than expected pitch, I thought it was good -- much better than being out ahead and grounding out to short
I'm pretty sure her intent was to make sure she was able to be on time for a fast pitch, more so than a delay for a slower than expected pitch. I've seen her use that before, but not very often. Usually, when she feels like she needs more quickness, she chokes up. I'm not sure why she chose to do it this particular time, but it worked.
