Raanta exited the game 15:37 into the period with the Hurricanes trailing the Rangers 2-0. As New York put the pressure on in the offensive zone, center Mika Zibanejad tried to get a stick on a bouncing puck near the crease. Raanta did a split to his right and then fell stomach-first to the ice as play was stopped.
Afterward, coach Rod Brind'Amour said Raanta's injury was serious enough he wouldn't have been able to play had Carolina advanced.
"No chance," Brind'Amour said. "He's going to get checked out tomorrow. That knee would've been out probably -- I don't know for sure, but he didn't look too good walking out of here, or limping out.''
Raanta entered the contest having gone 6-0 at home with a .965 save percentage and a 0.97 goals against average -- a primary reason Carolina hadn't lost a home game all playoffs. In Game 7, he gave up two goals on 18 shots, both on Rangers power plays.
The 32-year-old was signed last summer by the Hurricanes, after an eight-year NHL career that featured frequent injury absences.
He started 13 games, including Monday's Game 7, for the Hurricanes in the playoffs in place of starter Freddie Andersen, who last appeared on April 16 and missed the first two rounds with a lower-body injury.
Raanta's injury was the second significant one for the Hurricanes in Game 7; they lost Seth Jarvis, a rookie top-line winger, with about 12½ minutes left in the first period after a high hit by Rangers defenseman Jacob Trouba near Jarvis' left shoulder and head. The hit sent Jarvis sprawling to the ice and he could only crawl back to the bench.
Jarvis was too wobbly to even sit upright on the bench and needed assistance from teammates to get directed into the locker room.
"He might be on the smaller side, but he's feisty and he's got a lot of heart," defenseman Jaccob Slavin said of the 5-foot-10, 175-pound Jarvis. "Obviously he's a big component of our offense. ... It shouldn't change the outcome of the game but we definitely feel when his presence isn't there.''
Making matters worse, the Hurricanes took a penalty for too many men on the ice while trying to sub for Jarvis, with the Rangers' Chris Kreider converting 14 seconds later with a perfect redirect on a Zibanejad pass.
"That kind of summed it up right there on that shift,'' Brind'Amour said. "That was a tough blow in this game.''
The team soon ruled Jarvis out the rest of the night with what was described only as an upper-body injury.
The Associated Press contributed to this report.