2010-11: Joonas Lyytinen skated in eight games, including one playoff contest, for the KalPa Kuopio U18 team in Finland as a 15-year-old and played for the Finland U16 team. He scored 1 goal with 1 assist and 6 penalty minutes in seven regular season games and had an assist in the playoffs for the KalPa U18 team. In 28 games for the KalPa U16 team he scored 6 goals with 11 assists and 44 penalty minutes. Lyytinen had no points nor penalty minutes in two games with the Finland U16 team.
2011-12: Lyytinen played five games for the KalPa U20 team and was one of the top defensemen on the club’s U18 squad. He scored 1 goal with 3 assists and was +1 with 6 penalty minutes playing in the Finland A junior league. In 31 regular season games with the KalPa U18 team he scored 8 goals with 10 assists and had 40 penalty minutes. Lyytinen had no points and 2 penalty minutes in three U18 playoff games. He skated in 15 international games for the Finland U17 team and had 2 goals and 8 penalty minutes.
2012-13: Lyytinen spent the bulk of the season with the KalPa Kuopio U20 team — appearing in 34 games — and also played for Finland at the U19 and U18 levels. He scored 4 goals with 9 assists and was minus-1 with 30 penalty minutes in 31 A junior regular season games and was +2 with no points and 4 penalty minutes in three playoff games. He had 1 goal with 8 penalty minutes in four games for the Finland U19 team and had no points nor penalties in five games with the U18 team. Lyytinen was not part of Finland’s bronze medal squad at the U18 world championship in Sochi.
2013-14: Lyytinen took advantage of his opportunity to play in Liiga in what turned out to be a rebuilding year for KalPa Kuopio. Skating in the top pro league in Finland he scored 3 goals with 6 assists and was minus-3 with 24 penalty minutes in 30 games as KalPa finished last in the 14-team league; missing the playoffs. Lyytinen was an assistant captain for the KalPa U20 team prior to his call-up and in 24 games he scored 7 goals with 17 assists and was minus-7 with 32 penalty minutes. The KalPa U20 team also missed the playoffs. Ranked 94th amongst international skaters in the final Central Scouting rankings in his second season of draft eligibility, Lyytinen was selected by Nashville in the fifth round (132nd overall).
2014-15: Lyytinen skated in 52 of 60 regular season games for KalPa Kuopio in his first full season in Liiga and played for the Finland U20 team at the 2015 World Junior Championship. He scored 8 goals with 9 assists (one point behind Miika Koivisto for the team lead in points by a defenseman) and was +10 with 34 penalty minutes. Kuopio finished sixth in the regular season, falling to Lukko Rauma in six games in the playoff quarterfinals. Lyytinen was -2 with no points and 6 penalty minutes in six playoff games. Lyttinen had 1 assist and was +3 with 4 penalty minutes in five games for Finland at the WJC. Finland finished seventh after a 6-3 loss to Sweden in the quarterfinals.
Lyytinen is a strong skating defenseman with some offensive instincts. He is fairly early in his development curve and must refine all aspects of his game. He is responsible in his own end and maintains his composure in adverse situations. Lyytinen does not display elite stick handling or scoring skills nor is he a punishing defender but he is a positionally sound, reliable player in all three zones.
Lyytinen attended prospect camp with the Predators in July but has yet to sign an entry-level contract with Nashville and will return to Finland for at least one more season with KalPa Kuopio. At this point in his career it is difficult to determine his long-term potential — and there are several high-end defense prospects in the Nashville system — but he projects as a steady, two-way skating defenseman who can generate offense off the rush.