Career
He was selected eighth overall by the Sabres at the 2013 National Hockey League Entry Draft. Ristolainen made his National Hockey League debut with the Buffalo Sabres on the opening night of the 2013-2014 season, October 2, 2013, against the Detroit Red Wings. He scored his first career National Hockey League goal later in the month, on October 25, against Jacob Markström of the Florida Panthers.
He scored his first National Hockey League hat trick on December 10, 2015 against the Calgary Flames.
He was the first Sabres" defenseman to score a hat trick since the Hockey Hall of Famer Philosophy Housley in the 1987-1988 season.