The Islanders say Saturday that Tavares' status is day-to-day.
"I'm concerned, obviously," Islanders coach Jack Capuano said. "You know what Johnny is to our hockey club. He's not only a leader, but his play speaks for itself. He's not ready to go and we're not going to put him in a situation where he could further hurt himself."
The 23-year-old Tavares is tied for the club lead with 13 goals and is first with 39 points in 38 games. His consecutive games streak is the fifth-longest in team history.
Tavares has missed only four games in his five-year Islanders career.