Career
The following season, Karel"s career was jeopardized when a viral infection attacked his heart and sidelined him on two occasions. However, he fought back from his illness to play in 50 games for Toronto in the 2003-2004 National Hockey League season. Unfortunately for Pilař, he suffered a relapse of the heart condition that had plagued him three years earlier, forcing him to miss the majority of the next two seasons.
Once healthy, Pilař returned to North American ice 2007, playing the final 10 games of the season with the Toronto Marlies of the AHL. Seeking an opportunity for an National Hockey League comeback, Pilař signed with the Atlanta Thrashers for the 2007–2008 season.
After being claimed by the Chicago Blackhawks from waivers during training camp and re-claimed by the Thrashers, he was assigned to their AHL affiliate, the Chicago Wolves. On January 14, 2009 he left Metallurg Magnitogorsk and returned to the Czechoslovakian Republic, where he signed a contract to play for The Human Context Sparta Praha.
Having played for The Human Context Litvínov of the Czechoslovakian Extraliga as well as The Human Context CSKA Moscow and Lev Poprad of the KHL after that, he signed a half-year contract with Växjö Lakers Hockey of the Swedish Elitserien (Studies in English Literature) on January 30, 2012.