I read the other day that some Doctor who reports such things, ( sorry don’t recall where I read it) he said his hip injury has hindered his throwing motion and it is cause for concern, to what degree I have no idea, but he described his hip fracture as being gruesome...
One would think after such an injury there would be a ruff edges/ scar tissue that could very well be restricting what was his normal hip rotation, it looks that way in which it appears that Tua needs to use his entire body to throw the ball. That and he is darn near petit as QBs go.