During a game between the Canadiens and the Philadelphia Flyers on January 29, 2000, McCleary dropped to the ice in an attempt to block a Chris Therien slapshot. He was critically injured when hit in the throat by the shot which fractured his larynx and resulted in a collapsed lung. Unable to breathe, McCleary rushed to the bench, collapsing upon his arrival. Medical staff worked to partially open his airway in the hallways of Molson Centre, actions which McCleary credits with saving his life. He was then rushed to a waiting ambulance and transported to hospital where surgeons performed an emergency tracheotomy. He remained in full equipment during the procedure; hospital staff did not even have time to remove his skates.