Callahan left the ice cradling his left arm after he became tangled with the Flyers' Maxime Talbot in a post-whistle scrum. Both parties dropped their gloves, but Callahan grimaced in pain and never threw a punch before tumbling to the ice.
Earlier in the game, Callahan scored his second goal of the season, which turned out to be the game-winner as the Rangers edged the Flyers 2-1.
Rangers coach John Tortorella had no update on Callahan after the game and said he would be re-evaluated Wednesday.
I remember the first time at Wrigley Field all of us had the long johns, the turtlenecks and the extra equipment because we were afraid of being cold. Halfway through the first period everybody's ripping everything off and we just ended up wearing what we would normally wear for a game at the United Center.
— Chicago Blackhawks forward Patrick Sharp on the 2009 Bridgestone NHL Winter Classic