Newsday first reported on his status Thursday afternoon.
Pulock, the No. 15 overall pick in the 2013 draft, was called up from the AHL Bridgeport Sound Tigers in late February and saw action in 15 regular season games, scoring two goals and adding two assists.
In the playoff series against the Panthers, Pulock, 21, has scored one goal and registered two assists.
Pulock left in the third period of Game 4 on Wednesday night after a collision with Florida’s Garrett Wilson.
“It’s a big loss,” Islanders coach Jack Capuano told Newsday. “He’s a young guy who was playing real well, he had a couple points, a big goal (in Game 3). It’s a little more adversity we’ll have to battle back from.”
The series is tied 2-2 heading into Friday’s Game 5 in Sunrise, Florida.