Kostin will join Avangard, which began its regular season on Sept. 3, but will be available to return to training camp and play hockey in North America for the 2020-21 season.
Kostin was drafted by the St. Louis Blues in the first round (No. 31 overall) at the 2017 NHL Draft. He played in four regular-season games for the Blues in the 2019-20 season, posting one goal.
In three seasons with the AHL's San Antonio Rampage, Kostin has posted 29 goals and 53 assists (82 points) in 181 games.
