Ottawa coach D.J. Smith confirmed Murray's injury was the result of a knee to the head from Rangers forward Chris Kreider, but he had no further update. Anton Forsberg, without any time to warm up, was forced into action in the third period, and he quickly allowed two goals to Ryan Lindgren and Barclay Goodrow, respectively, as the Rangers rallied to win their fourth straight game, all on the road.
Alexandar Georgiev made 26 saves for New York, and Kreider scored his fourth goal of the season in the win.
"You could definitely feel the momentum change," Georgiev said of the third period. "And when I saw them change the goalies, too, unfortunate for them but, luckily, we played great after that."
Ottawa led 2-0 after Josh Norris' goal early in the third period, but the Senators unraveled late.
The Senators have big plans for Murray, who stopped 22 shots before leaving. Acquired from the Pittsburgh Penguins before last season, Murray signed a new deal with Ottawa this summer, totaling $25 million over four years. Murray won two Stanley Cup titles with the Penguins.
But Goodrow scored the winner on Murray's replacement with 2 minutes, 3 seconds left by deflecting a long shot from Sammy Blais.
"I thought we carried the play for 54 minutes, made some bad plays and ultimately end up losing a game you shouldn't lose," Smith said.
Georgiev, making his second start of the season, made an incredible point-blank save on Artem Zub in the final minutes of the second period.
"Every bounce went their way," Smith said.
The Associated Press contributed to this report.