Mannion is a RFA next year so they could be hedging their bets about him. Now that they're into the season there's not as much "teaching time" available- certainly not for a #3 QB. But they can get a sense of him and see how he learns the system, how he fits into the QBs meeting room, etc. Maybe he actually competes for the #2 job next year, maybe he gets dumped in February. Who knows...