Koltsov started playing for Junactva Minsk in the
Belarusian 1st division during the 1997–98 season and moved to the Russian team
Severstal Cherepovets for the next season. Due to his speed and stick handling, he was often referred to as the "Russian Rocket II" because of his similar playing style to that of Russian great
Pavel Bure. He played for the
Wilkes-Barre/Scranton Penguins in the
AHL in the 2002–03 season and started playing full-time for the
Pittsburgh Penguins in the 2003–04 season, playing 82 games and scoring nine goals and 20 assists. During the
2004–05 NHL lockout, Koltsov played for the
Spartak Moscow hockey team, scoring six goals in 31 games. With Salavat Yulaev Ufa, Koltsov won the
Gagarin Cup throughout the 2010–11 season. On November 27, 2016, Koltsov retired from professional hockey after competing for 18 seasons. He became an assistant for the Belarusian men's hockey team and also worked as the assistant coach of
Salavat Yulaev Ufa, where he served for two seasons prior to his death. ==International play==