Staal was struck in his right eye by a deflected puck in the game against the Philadelphia Flyers.
"Marc Staal was examined today in New York by Dr. Mark Fromer, ophthalmologist, and Dr. Mendel Markowitz, maxillofacial surgeon. The injury has improved significantly and both doctors are optimistic that Marc will make a full recovery. Staal will be sidelined indefinitely," the Rangers said in a statement Wednesday evening.
Staal was injured 5:45 into the third period when Kimmo Timonen's redirected slap shot from the point hit him in the face, around his right eye. He fell to the ice and was writhing in pain as blood poured out of his face.
Staal, who does not wear a visor, eventually was able to skate off while covering his eye to stop the blood from dripping out.
"It's a tough, tough one," right wing Rick Nash said after the Rangers' 4-2 victory. "We're hoping the best for him; just hoping it's not the thing we all think it is."
Goalie Henrik Lundqvist said he believes the puck hit Staal flush on the right eye, leaving him with cuts above and below his eye. Dan Girardi, Staal's defense partner, said he was engaged in the corner with Flyers forward Scott Hartnell so he didn't see the puck hit Staal, but he heard it.
"It was scary," Lundqvist said. "He was in a lot of pain. It was tough to focus after that, really tough."
Staal had played in every game this season after a concussion forced him to miss the first 38 games of last season. He made his debut in the 2012 Bridgestone NHL Winter Classic against the Flyers.