2008-09: Klassen caught the attention of Rangers' scouts with his gritty defensive play and ability to support the attack in his second full season with WHL Saskatoon. Klassen was one of three Blades defensemen with over 90 PMs (he had 92) and also scored 2 goals with 18 assists in 72 games. Klassen finished with a +27 plus/minus. He skated in all seven games as East Division champion Saskatoon lost to Lethbridge in a first round playoff series. He had 1 assist and was +2 with 10 PMs in the post-season. Klassen signed a free agent, entry-level contract with the Rangers in July 2009.
2009-10: Klassen returned to the WHL after attending Rangers camp and appeared in 67 games with Saskatoon. Klassen was second to Sfefan Elliott (COL) in points for Blades' defensemen while accumulating 98 PMs. He scored 3 goals with 27 assists and had the team's third-best plus/minus (+34). The Blades advanced to the second round of the WHL playoffs after finishing second in the East Division and Klassen played in all 10 playoff games. He had 2 assists and was +8 with 8 PMs.
2010-11: Klassen appeared in three AHL games with Connecticut in his first pro season; spending the majority of the season with Greenville in the ECHL. Klassen skated for the Whale in three mid-January game and was scoreless with an even plus/minus and had 4 PMs. In 66 games with Greenville he scored 3 goals with 14 assists and was +16 while racking up 80 PMs. Klassen skated in all 11 ECHL playoff games for the Road Warriors and was +5 with 2 goals, 3 assists and 8 PMs.
A tough blueliner, Klassen can intimidate anywhere on the ice. However, he does not have the speed or balance to play the game at the NHL level.
When signed by the Rangers in 2009, it was thought that he was ready for professional play. Fall training camps showed he was not and Klassen was returned to junior hockey for an overage season. In his first professional season, he played at the ECHL level. It is likely that he will continue at this level until the end of his ELC.