Barkov collided knee-on-knee with Islanders defenseman Scott Mayfield with 18 minutes, 13 seconds left in the second period. Barkov remained on the ice for several minutes before leaving the game, putting no weight on his left knee. He did not return to the game.
Panthers interim coach Andrew Brunette says Barkov will be evaluated over the next couple of days but didn't give further updates.
"It's a test again,'' Brunette said. "We've had a lot of tests this year; this is another one. You hate to lose Barky. He means so much to this franchise. Hopefully he's OK."
Mayfield, who appeared to lean into the hit, was assessed a five-minute major and a game misconduct.
"There wasn't a big window as Barkov came laterally between him [Mayfield] and another player,'' Islanders coach Barry Trotz said. "He looked like he was trying to hit him shoulder to shoulder. I know Scott. There's no intent there. It's all in the interpretation."
The Associated Press contributed to this report.