They basically are one in the same. I thougth I stated this in the forward, but I could be incorrect. I went back to the tapes this morning and one thing that really brought to my attention is the mimicing movements between the sink and change up. I tend to think he three 4 straight change ups over sinkers. What was funny is that I checked Jordan's block quote and he threw a clear amount of change ups. I think this makes my comment of adding a circle change 100% correct.
He throws a two seamer that can split both ways. He can whip in on a right hander and it is east/west like a cutter. He also will place presure on the middle finger to exaggerate his nature left dip. What you have to realize is that most left handers have a natural movement in on right handers. Straight changes, when working, will dip in on a right handed batter.
Zach throws two different variations. One sits in the low 90's and more quick snap than drop off. His one that sits in the upper 80's has a bit more drop. He threw it with some success, but there were some dirtballs.
Well back off my zoom...there was a clown running on the field and I thought I would check this out for questions. I will talk more shop once the game is over and I head home.