2010-11: Radel Fazleev played for the Ak Bars Kazan's 1996-born that won the Russian national championship and he represented the Povlzhie region in Russia's U-15 national tournament. Ak Bars won the Povolzhie region championship and Fazleev scored 3 goals with 3 assists and was -1 with 4 penalty minutes in five games at the Russian championships. In five games for Povolzhie he scored 1 goal with 5 assists.
2011-12: Fazleev skated for Ak Bars Kazan, which won the Russian U17 national championship, and he played for Russia's U16 team in the Red Bull Rookies Cup. After winning the Povolzhie region championship, Ak Bars finished second in pool play to Avangard Omsk but defeated Omsk, 4-1, in the playoff round championship game. Fazleev scored 2 goals with 3 assists and was -1 with 6 penalty minutes in six games at the Russian championships. He scored 1 goals with 3 assists in four games for Team Russia at the Red Bull Rookies Cup.
2012-13: Fazleev played in Russian junior hockey as a 16-year-old — skating in 9 games for Bars Kazan in the MHL and spending most of the year in the MHL B league with Irbis Kazan. He played in five tournaments for Russia's U17 team including the 2013 World Hockey Challenge. He had no points nor penalties skating for Bars Kazan. Fazleev scored 7 goals with 10 assists and was +7 with 8 penalty minutes in 23 regular season games for Irbis and scored 1 goal with 2 assists, finishing -4 with 4 penalty minutes, in five playoff games. In six games for Russia at the WHC he scored 3 goals with 4 assists and had 2 penalty minutes. Russia lost to Sweden, 7-5, in the gold medal game. Fazleev was selected by Ak Bars in the first round (ninth overall) of the 2013 KHL Draft and was a first round pick (52nd overall) of Calgary in the 2013 CHL Import Draft.
2013-14: Fazleev played for Russia's U18 team in the 2013 Ivan Hlinka Memorial Tournament in August before joining the WHL's Calgary Hitmen. He played 38 regular season games for Calgary in his first season, suffering a broken wrist at the beginning of January that kept him out the lineup until the start of the playoffs. Fazleev scored 5 goals with 20 assists and was +1 with 12 penalty minutes. The Hitmen finished first in the Central Division. Fazleev scored 1 goal with 2 assists in four games for Russia at the Ivan Hlinka tournament. He was ranked 129th amongst North American skaters in Central Scouting's mid-term rankings prior to the 2014 NHL Draft.