Career
He is currently playing with the Rochester Americans in the American Hockey League (AHL) as a prospect for the Buffalo Sabres of the National Hockey League (National Hockey League). He was selected by the Buffalo Sabres in the sixth round (163rd overall) of the 2012 National Hockey League Entry Draft. On May 27, 2014, Ullmark was signed by the Sabres to a three-year entry level contract.
He was returned on loan to Modo Hockey of the Swedish Hockey League for the 2014-2015 season.
In his first season in North America, Ullmark attended the Sabres training camp. After recovery from an early injury, he was assigned to begin the 2015-2016 season with the Rochester Americans of the American Hockey League (AHL).
Ullmark played in three games before being recalled to the Sabres on October 23, 2015. Ullmark made his National Hockey League debut with Buffalo the following day, making 24 saves in a 4-3 defeat to the New Jersey Devils.