John Tavares is week-to-week with a lower-body injury, team officials announced on Saturday.
Tavares' foot got caught the net behind the Devils goal and the Islanders captain fell awkwardly to the ice before being helped back to the team's locker room with 3:14 to play in the third period of Friday's 2-1 win.
"It's a big blow anytime you see your best player go down," Interim Coach Doug Weight said on Friday. "These guys have been around. Injuries happen. It's not fun, but it gives somebody a chance."
Tavares leads the Islanders with 66 points (28G, 38A) in 77 games this season. The Islanders captain led all forwards with 20:25 TOI per game, was tied for the most power-play TOI per game (3:11) on the team and had even become a steady penalty killer for the first time in his career this season.
"It's not a great scenario, obviously," Weight said. "John is a huge engine and plays every single situation we've asked. What are you going to do? We have to figure out how we're going to get up here… We need a guy to come in, step in and contribute and we need the guys that played better today to keep pulling more rope. There are 10 points out there that we need."
With Casey Cizikas, Ryan Strome and Nikolay Kulemin also out, the Islanders are down to 11 forwards.
The Islanders have five games left in their regular season and are back in action on Sunday afternoon in Buffalo.