I think the pundits who believe that Marc Bergevin, rightly or wrongly, will largely stand pat at the deadline are on the right track. I would guess that the team has surprised him, in almost an awkward way, in how well it has performed the last couple of seasons, hampering his ability to trade assets for a true rebuild. Instead, he has to retain players for a putative playoff run. You always like to win, it's good for morale and the organization, but possibly some plans have had to be scrubbed.
On the other hand, he does not have the chips to wheel and deal like the Penguins or the Blues might. If Jarred Tinordi, Nathan Beaulieu and Greg Pateryn had developed really quickly, and were now ready to be fixtures on the blue line, and/or if there was a junior-age player ready to jump into the lineup next season like a Boone Jenner or Brandon Saad, he could consider dealing veterans or more marginal prospects for upgrades to make a playoff run, but we're not there. Our prospects are developing, but the pipeline isn't gushing as of yet, so he doesn't have much to swap with. Any acquisition will leave a hole somewhere else. Beefing up the blueline will deplete the forwards or the store of draft picks, and so on, we'd be robbing Peter to pay Paul.
So again this trade deadline, we should be reasonably confident that the Canadiens won't be a major participant in the proceedings. Before the draft should see more activity, with contracts expiring and decisions on players being made.