Sometimes its the best decision not to throw someone into the fire, and that could be the case with Mannion. Maybe he has some bad habits and/or mechanical issues he needs to break out of; putting him into a game speed action might revert him back into those bad habits. Sitting on the bench allows time for him to get fully accustomed to whatever he's learned in the NFL. I'm only throwing out w/e could be the reason(s) as to why he's not starting. Now I'm not saying Mannion is Rodgers, but that's something Rodgers did work when he was on the bench, working on his mechanics. Maybe its that sort of issue with Mannion, idk. I personally agree that he should stay on the bench and keep learning, although one could argue that game action can be the best way to learn and improve. I don't disagree with that notion either, just perception at this point.