Trevor Bauer uploaded a video talking about his pitch design, including a ton of high-speed video focusing on how he actually releases the ball:
The overlay video at the end is especially cool, with this map of his intended destinations for all of his pitches:
His pitches in question are:
Reverse slider (screwball/sinker; intent is to map precisely to a lefthander’s cutter/slider)
For those wondering why he throws so many pitches, it might be beneficial to first understand Perry Husband’s theories on pitching, covered in a set of three books. He recently released the first one (Downright Filthy Pitching) on Amazon in Kindle format for just $10. It’s a unique and different look on pitch tunnels and how hitters actually perceive velocity/location:
While I don’t agree with all of his information (he contends that batted ball exit speed is highest on ground balls, which may be true, but doesn’t mean they have the highest run value; Husband doesn’t look much into advanced sabermetrics of batted ball data), it was revolutionary for its time, written more than eight years ago using Inside Edge data.
For those who want more information on what Trevor Bauer was talking about in regard to pronation in the delivery, I did a follow-up video that discussed what he and I worked on while he was in Seattle, along with a lot of in-depth analysis of pitching mechanics and applied anatomy: