Ryazantsev signed for Rubin Kazan before the start of the 2006 Premier League season. His first appearance was as a substitute in a match against Spartak Moscow. He appeared in the starting lineup in the home match against Krasnodar and managed to score a goal. He was also a starter when the team won the 2007 Russian Premier League. In 2008 Russian Premier League Ryazantsev brought his team into champions Rubin Kazan in the Russian Premier League in 2008, he appeared 22 times and scored 1 goal and 3 assists.