Koalska made his professional debut with the Bridgeport Sound Tigers of the American Hockey League in the 2004–05 season. He appeared in three NHL games with the New York Islanders in the 2005–06 season, going scoreless."Player bio" NY Islanders On January 5, 2007, the Islanders traded Koalska to the Ottawa Senators in exchange for defenceman Tomas Malec. Koalska finished the season with the Senators' AHL affiliate, the Binghamton Senators before signing in the off-season with HC Bolazno in the Italian Elite League. However, Koalska did not play with Bolazno, having to retire due to a heart condition. He returned to University of Minnesota to complete his degree.
