An MRI taken Friday showed that the 22-year-old center has a Grade 3 sprain of his medial collateral ligament and a partial sprain of the posterior cruciate ligament. The injuries won't require surgery.
"It's stiff, but I knew it was going to be worse today," Lundmark said Friday. "I can't really move it."
Lundmark was injured Thursday night when New York Islanders captain Michael Peca took him out with a leg-to-leg check in open ice. The hit was called intentional by Rangers coach and general manager Glen Sather and several other players.
"It is a reaction," Sather said. "You don't need to knee a player to take a guy out. I'm sure he's not thinking he's going to take his knee out when he does it."
Peca contends that there was no intent to injure, and he walked to the Rangers' dressing room to apologize to Lundmark after being ejected from the game.
"It's a nice gesture on his part," Sather said. "I can't say that makes what he did right."
Peca was given a major penalty, and the Rangers turned the advantage into two power-play goals that sparked their 4-2 victory.
Lundmark saw a replay of the check, but he wouldn't say whether he thought the shot that caused his first big injury was done on purpose. He was surprised when Peca walked down the hallway to see him.
"I wasn't really expecting it. It caught me off guard," Lundmark said.
Lundmark was injured while playing his fourth straight game after missing the previous three as a healthy scratch. He has two goals and five assists in 23 games this season.
In his rookie season of 2002-03, Lundmark -- the No. 9 overall pick in the 1999 draft -- had eight goals and 11 assists in 55 games.