From what we've seen so far, Serge is not ready for the NHL. With that being said, he has shown to be a quick learner in the past. Given this, I would not be surprised to see Bergevin give him a 9 game trial to see where he is at the end of these 9 games.
You can definitely see the potential and the confidence in his play but you can also see he needs time to adjust to the speed of the NHL. Is 9 games plus a few pre-season game enough? If I was Habs management, I would be curious to know.
I think the smart move is to play the hell out of him in the last 2 remaining game as part of a good NHL lineup and see how he does.
But then, the question would be: Who does he replace? I don't think any of Pateryn, Markov, Emelin, Petry, Beaulieu or Weber deserve to sit for Serge.
We would need to play with 7 D, a system which I personally dislike.
Unless he is an absolute beast out there in the last 2 games, I think he gets sent down.