2008-09: Fredrik Claesson competed for Stockholm 1 in the national TV-Pucken high school age tournament and scored 3 goals with 3 assists in six games. Claesson played his club hockey for the Djurgarden U-18 and U-20 teams. At the U-20 level, he appeared in seven games with no points or penalty minutes. In 28 games at the U-18 level, he scored 9 goals with 8 assists and registered 4 PMs. Claesson played six games for Sweden's U-17 team and had one assist.
2009-10: Claesson split the season between Djurgardens U-18 and U-20 teams as well as representing Sweden at the World Junior U-18 championships. In 22 games with the Djurgarden U-20, he had 4 assists and 18 PMs. In eight games with the U-18 squad (including playoffs) he scored 1 goal with 4 assists and accumulated six penalty minutes. Claesson had one assist in six games at the WJC U-18 tournament.
2010-11: Claesson appeared in 35 regular season games and seven playoff contests as a rookie for Djurgardens in the Swedish Elite League. A teammate of Senators' 2011 first round pick Mika Zibanejad, Claesson played the role of a classic defensive defenseman and was +4 with two goals – scoring despite the fact he took just 18 shots the entire season. In seven playoff contests, he was +3 with one assist and 2 shots on goal.
2011-12: Claesson had an eventful second pro season – winning a gold medal at the U20 World Junior Championship in January with Sweden and then suffering the ignominy of seeing his Djurgardens squad relegated from the Elitserien to the second division, AllSvenskan. Claesson had 1 goal and 6 assists and was plus-seven in a career-high 47 Elitserien games. After finishing eleventh, Djurgardens failed to retain one of the two available Elitserien spots – finishing third in the Kval Series. Claesson was an even plus/minus with 1 assist in the ten Kval games. He played six games for Sweden at the WJC and was an even plus/minus with no points nor penalty minutes. Sweden defeated Russia in the gold medal game. Claesson signed a three-year, entry-level contract with Ottawa in May, 2012.
2012-13: Claesson skated for Ottawa's AHL affiliate in Binghamton in his first pro season in North America. Making his AHL debut as a 19-year-old, he scored 3 goals with 8 assists in 70 games and was +4 with 51 penalty minutes. The Senators were second in the East Division and had the AHL's fourth-best record before being swept by Wilkes-Barre/Scranton in a first round series. Claesson had 1 assist and was +1 with 2 penalty minutes in three playoff games.
Claesson is almost exclusively a stay-at-home defenseman. While not overly physical, he plays a sound positional game and is very good at preventing scoring opportunities and blocking shots and passes. Claesson is not an impressive stickhandler at this point in his career but those skills should improve as he continues to develop.
Claesson is playing for Binghamton of the AHL for the 2013-14 season. What separates Claesson from the other young Senators defenders is that he is almost exclusively a defender rather than an attacking blueliner. Claesson's success against older competition at a young age is also a plus. Long-term, Claesson projects to being a depth, stay-at-home defenseman after a few more seasons of development.