I didn't even know he was on the DL. Whew. Though if Rizzo is crazy enough to keep HRod after all he's done, I wouldn't be surprised if he did what you described. "He just has so much potential."
I always wanted to be a scout and have extensively watched batters swings and pitchers mechanics and I have to agree with Rizzo here. I understand Henry is awful but honestly his delivery is compact, clean, fluid and over the top. He hides the ball well and has no timing issues. From the batters eye, it's as if he is throwing just like a guy who has impeccable mechanics and throws in the high 80's (Think Maddux here) but the ball comes out INSANELY fast. Usually when you look at guys who have insane velocity, they have very large deliveries which means the batter has the ability to time the pitch to the plate and adjust accordingly. Just look at how Dan Uggla can POUND a SS fastball out of the park. Henry lets the ball rip and because it comes into view so quickly due to his delivery, the batter needs to guess to adjust. Most of the time they guess wrong. Then he comes out with the SAME DELIVERY to pitch the change and the slider. This is incredibly hard to do and because he hides the ball and conceals his delivery so well the hitter HAS to assume a FB is coming so he sits on that.
Saying all that, he can't put a damn pitch in the zone. This means guys will just let him walk them. Henry is his own worst enemy. If he can figure it out, Rizzo has a gold mine on his hands because he honestly has nastier stuff than Kimbrel who is nasty for all the same reasons as Henry, but obviously he can locate.