MONTREAL — Prognosis: Who knows?

The Rangers provided no update regarding Antti Raanta’s health after the netminder was forced out of Saturday’s match against the Canadiens after having sustained a first-period “lower-body” injury.

So it is anyone’s guess whether the Rangers will be without their invaluable backup — who turned in a spotless first period in what became a 5-4 defeat — for any length of time.

If Raanta is sidelined, 25-year-old Magnus Hellberg is the logical candidate to get the call from the AHL Wolf Pack. Hellberg, who made one relief appearance with the Rangers last season, is 10-9-1/.905/2.91 this season.

So, with five games remaining before the All-Star break, beginning with Tuesday’s match at the Garden against the Stars, Henrik Lundqvist may indeed get a run of starts. And, it appears as if the notion of the Rangers being whole for the first time in months might have to be put on hold for a while.

Similarly, the Blueshirts had no information regarding the status of Marc Staal, who has now been sidelined for four games with post-concussion symptoms.

The alternate captain, who had suffered two previously recorded concussions, has not played since Jan. 3.

The Rangers amended their plan to rest Pavel Buchnevich in this second game of the back-to-back that commenced with Friday night’s Garden defeat to the Maple Leafs. The winger, who played 10:43 in that one, got 17:39 against the Canadiens playing on a line with Kevin Hayes and Rick Nash.

Coach Alain Vigneault used Buchnevich, who had two shots on net, after pulling Lundqvist for an extra attacker with 1:43 remaining.

Brandon Pirri ’s first period goal on the power play that gave the Rangers a 1-0 lead was his first in 12 games since Dec. 11. … Canadiens goalie Carey Price foiled Michael Grabner ’s breakaway bid to tie the game with 4:35 to go in the match. … J.T. Miller scored his league-leading third shorthanded goal of the year at 11:07 of the second period off a 2-on-1 feed from Hayes.

Mats Zuccarello has gone 12 games without a goal and 27 games without one against a goaltender since beating Jacob Markstrom in Vancouver on Nov. 15. Zuccarello, though, has 12 assists in his past 11 contests, including one Saturday while playing with Chris Kreider and Derek Stepan on the club’s most formidable unit.

“I’ve never evaluated my game by goals or even points,” Zuccarello, who has eight goals after getting a personal-best 26 last season, told The Post. “I feel like I can have my best game and not score a goal and then struggle in the next game and get two or three.

“I feel like I’m creating chances at one end and I think I’m doing the job in the defensive zone, blocking shots and doing what I can there. It’s about the team, not any one individual.”