It would be pretty wild if he gets sent down without tasting regular season action at this point.
It appears he has turned heads with his defensive game, and the offensive output is a bonus. If he can play a few games and platoon with JBD and Hamonic, that is great. He earns some NHL chedda, practices with NHL players and continues to soak up experience.
I think the expectation is that he ends up back in junior as he goes through the inevitable rookie slump and trials/tribulations, but ride is out as long as he can.
In the summer, I don't think he made himself a lock for Team Canada, but this should certainly raise his stock and unless he is a legit NHL regular, I can't imagine the Senators keeping him from playing for TC in Ottawa, so he goes back down then.