The Islanders are going to be without Anthony Duclair for a while. 

General manager Lou Lamoriello told reporters before the team hit the ice for Monday’s practice that the winger’s injury would be “more long term than short term at this point,” though it would not be season-ending. 

An exact time frame isn’t yet known, with the Islanders waiting on MRIs and X-rays. 

Duclair appeared to suffer a right leg injury during Saturday’s win over Montreal, going down hard in the third period and not getting up. He was helped off with no weight on his right leg. 

“We don’t like those injuries, especially the ones that could be long,” coach Patrick Roy told reporters. “So it’s always tough to lose a player like that.” 

The summer’s marquee signing for the Islanders, Duclair already had two goals and an assist in the season’s first five games, and looked to be building chemistry with Mat Barzal and Bo Horvat on the top line. 

That top unit, which featured three high-end skill players with Duclair added, was one of the biggest reasons to believe the Islanders could improve this season from being a fringe playoff team to a legit contender. 

The lineup ramifications aren’t 100 percent clear just yet, as the Islanders have yet to call anyone up from AHL Bridgeport after Julien Gauthier cleared waivers Monday afternoon.

But Simon Holmstrom got the first crack at Duclair’s spot on the top line during Monday’s practice, with Casey Cizikas moving up from the fourth line to Holmstrom’s spot on the third. 

“I think he’s super skilled with the puck,” Horvat said of Holmstrom. “He’s smart at both ends of the rink. I think he’s definitely got the speed and everything to stay with Barzy and be on the rushes with us. He’s a great player. If we get the opportunity tomorrow [against the Red Wings], we gotta make the most of that.” 

Pierre Engvall, who surprisingly did not make the team out of camp, and Hudson Fasching are the likely call-up candidates.

If it is Engvall, the Islanders would need to officially place Duclair on long-term injured reserve — which would mean a minimum of 24 days and 10 games before he returns — or find some other way to clear space in order to fit Engvall’s cap hit. 

Also if Duclair hits LTIR, the Islanders would have enough cap space for multiple call-ups, which could bring Liam Foudy or Fredrik Karlstrom into play, after both impressed during training camp. 

Gauthier being waived on Sunday looked like an indication that the Islanders would not need LTIR, but in fact had to do with Roy disliking his performance in what amounted to an audition on the fourth line. 

“I just expect more from him,” Roy said. “I was not comfortable to put him [in] at the end of the game. We wanted to win that game badly. I was just not comfortable to put him out there. I guess that tells you everything.” 

Matt Martin, who is still practicing with the Islanders on a tryout contract, is not being considered as a full-time signing, Lamoriello told reporters.