2009-10: Olli Maatta played for JYP's U-16 squad for most of the season. In 28 games for that team, he scored 15 goals and added 26 assists for 41 points to go along with 32 penalty minutes. In 3 playoff games, Maatta picked up 1 assist.
2010-11: Maatta split the season between the D Team in the Finnish second league, and JYP's U-20 team. In 23 games for the D Team, Maatta scored 1 goal and added 5 assists for 6 points. In 19 games for JYP, he scored 2 goals and added 6 assists for 8 points. In 12 playoff games for JYP, he scored 1 goal and added 4 assists for 5 points. Maata played for Finalnd's entry at the 2011 U-20 World Junior Championship, registering no points in 6 games. Maatta also played for Finalnd at the 2011 U-18 World Junior Championship, scoring 1 goal and adding 3 assists for 4 points in 6 games. Maatta was named a Top 3 Player for his team in this tournament. Maatta was chosen in the first round, 1st overall, of the 2011 CHL Import Draft by the OHL's London Knights. Maatta was also chosen in the fourth round, 85th overall, of the 2011 KHL Draft by SKA St. Petersburg.
2011-12: Maatta spent his first season playing in North America; skating for the OHL's London Knights. He was expected to be a key part of a possible medal run for Finland at the 2012 U20 World Junior Championship but his tournament ended abruptly after an injury in the first game. Maatta was a big part of the success for the Knights, who had the league's best record and faced Niagara in the OHL Finals. Limited to 58 games due to the concussion he suffered in the WJC, Maatta scored 5 goals with 27 assists and was plus-25 with 25 penalty minutes. In 14 playoff games entering the OHL Finals, he scored 5 goals with 14 assists and was plus-11 with 2 penalty minutes. Central Scouting rated Maatta eighth amongst North American Skaters in its final rankings prior to the 2012 NHL Draft.
2012-13: Maatta signed a three-year, entry-level contract with Pittsburgh in September of 2012 before returning to London for his second OHL season. He made his pro hockey debut following the Memorial Cup and competed for Finland in the 2013 World Junior Championship. Maatta joined the AHL Penguins at the end of May and was -2 with no points nor penalty minutes in three AHL playoff games. He scored 8 goals with 30 assists in 57 games for London and was +9 with 30 penalty minutes. London captured the OHL championship, rallying from a 3 games to 1 deficit in the finals against Barrie. Maatta was +10 with 4 goals, 10 assists and 8 penalty minutes in 21 playoff games. He was scoreless with no penalty minutes and an even plus/minus in four Memorial Cup games. Maatta played five game for Finland, missing one game due to illness, and was even with 1 goal and 2 assists. Finland finished seventh.
The foundation of Maatta's game is built around consistent, non-flashy play that should make him a solid contributor in the NHL for years to come. Though not initially known for his offensive output, Maatta possesses excellent vision, hockey IQ, and puck-distribution ability, leading many to believe he has some untapped offensive potential. But steady play in the defensive and neutral zone is what Maatta does best, and with his mobile skating ability, he should develop into a solid NHL defenseman in the not-too-distant future.
One aspect of his game which needs worked on is his confidence. As a defenseman in the OHL, he is put in a lot of tough defensive matchups, which can lead to him trying to do too much. He is also streaky offensively. He also needs to continue to get stronger and fill out his large frame.
Maatta will rejoin the London Knights for the 2013-14 season where he will take on greater minutes and responsibilities. Ultimately he projects as a two-way defenseman who can play top four minutes.