From multiple sources (including the New York Rangers official twitter):
Drury won't be making the road trip with the team, Erik Christensen will be returning to the lineup tomorrow for the Rangers who travel to Montreal to face the Habs. Erik Christensen had a second degree MCL sprain, he was injured December 29th in a contest against the Devils. He was expected to miss 4-6 weeks and was reported as 'day-to-day' last night during the broadcast on MSG. Christensen had said that his knee was fine and that the only thing keeping him out of the lineup were his lungs (conditioning).
Torts on Drury: "He has had cranky knee and has progressively gotten worse...this has gone a few weeks & flared up again last night"
Torts: "He's played this game hard for a long time and I think it's a little bit of wear and tear...and it's just acting up on him now"
The captain is a scratch and 'likely won't make the road trip' with his knee. The Rangers have a 3-game road trip coming up: February 5th in Montreal, February 7th in Detroit, and February 11th at Atlanta. If Drury doesn't make the road trip altogether he stands to miss the next three games.
Torts also said the following about Christensen:
"He's a skilled guy and he's going to add to us, something we need, and I think he'll fit right in... he's excited to play." -via New York Rangers twitter feed