I'm no pitching coach, but I did pitch at one point in my life, so I at least have a teeny tiny bit of knowledge on the subject. It seems like when Yo gets wild, he misses up a lot. And when he misses up, it appears to me that he's not following through on his delivery enough. Basically, what I'm seeing with my amateur eye is that his release point ends up too high and on too much of an upward angle. I love him, though. Everybody has bad innings/games sometimes.