The injury came in regulation during the Islanders' 3-2 win against the Tampa Bay Lightning after Barzal dove to stop a shot.
Barzal, a key piece to the Islanders as their most dynamic player, has six goals and 14 assists in just 30 games this season after missing time earlier in the year due to an upper-body injury, which sidelined him for almost two months from November 1st to December 17th.
The Islanders have been the hottest team in hockey recently. Before losing to the Florida Panthers on Sunday by a score of 6-3. the Isles were on a seven-game win streak, their highest of the season.
Injuries keep on piling on the Islanders. Defenseman Scott Mayfield (32) also left the game with a lower-body injury but is considered day-to-day. If Barzal does end up going on the long-term IR, the team will open up $9.15 million in cap space.
The New York Islanders are currently 24-21-7 and sit in fifth place in the Metropolitan Division. This week, the team will face a tough slate of teams in the Winnipeg Jets, Minnesota Wild, and Dallas Stars.