The 19-year-old Russian began the season in the NHL, but struggled to adapt. He scored two goals in 18 games before being demoted to the Quebec Remparts of the Quebec Major Junior Hockey League on Jan. 11.
Grigorenko initially refused to report to Quebec, preferring to develop in Rochester of the American Hockey League. An agreement between the NHL and the Canadian Hockey League does not allow teenagers to play in the AHL.
Buffalo would've likely preferred Grigorenko play for Rochester. The Sabres tried to send Grigorenko to Rochester on a conditioning assignment in November, but the NHL denied the request.
Grigorenko has dominated at major junior level, scoring 178 points over parts of three seasons with Quebec. He had 48 points in 28 games for the Remparts after his demotion.
With the Remparts' season over, Grigorenko is allowed to play in the AHL.