2010-11: Marcus Pettersson played for the Skelleftea club in northern Sweden and skated for bronze medal-winning Vasterbotten in the TV-Pucken tournament for high school players. He skated in two Allsvenskan U18 games with no points or penalties and had 1 assist in three games for the club’s top U16 team. Petterson scored 3 goals with 4 assists and 4 penalty minutes in eight TV-Pucken games.
2011-12: Pettersson skated for Skelleftea’s silver medal-winning U18 team, played 10 international contests with Sweden’s U16 team and was a team captain for TV-Pucken champion Vasterbotten. He scored 5 goals with 7 assists and was +17 with 12 penalty minutes in 33 regular season games for the U18 team. Pettersson scored 1 goal with 3 assists and was +8 with 14 penalty minutes in seven playoff games. He was +15 with 1 goal, 1 assist and 4 penalty minutes in 10 games for Sweden’s U16 squad. He scored 4 goals with 5 assists and was +11 with 8 penalty minutes in eight TV-Pucken games.
2012-13: Pettersson competed for Skelleftea in Sweden’s U20 SuperElit league as a 16-year-old and played for Sweden in the 2013 World U17 Hockey Challenge. He scored 4 goals with 8 assists and was +4 with 16 penalty minutes in 37 regular season games and was -1 with no points nor penalties in two SuperElit playoff games. Pettersson had no points and 4 penalty minutes in six games at the WHC. Sweden defeated Russia, 7-5, in the gold medal game.
2013-14: Petterson made his pro hockey debut with Skelleftea in Sweden’s SHL and is an assistant captain for the club’s U20 team. He was +2 with no points and 2 penalty minutes in his first 10 SHL games. Pettersson scored 2 goals with 11 assists and was +1 with 34 penalty minutes in his first 27 SuperElit league U20 games. He was ranked seventh amongst International skaters in the Central Scouting final rankings and was selected by Anaheim in the second round (38th overall) in the 2014 NHL Draft.
2014-15: Pettersson split the year between the Skelleftea men’s team in the SHL and the club’s junior team and also played for Vita Hasten in AllSvenskan. He skated for the Sweden U20 and U19 teams but was not on the final roster at the 2015 World Junior Championship. He was -1 with no points in 14 SHL games. Pettersson scored 2 goals with 2 assists and was +5 with 16 penalty minutes in 10 regular season games for Vita Hasten. In nine qualification playoff games he scored 1 goal with 2 assists and was -2 with 8 penalty minutes as Vita Hasten avoided relegation. In 20 games for the Skelleftea U20 team he scored 2 goals with 8 assists and was -4 with 20 penalty minutes. Pettersson signed a three-year entry-level contract with Anaheim in June 2015.
Pettersson is a tall, intelligent defenseman who has a long reach and rarely allows opponents to get around him, gobbling them up as they try to pass. He uses his sizes effectively in orchestrating a very effective pokecheck. He has a strong sense of one-on-one positioning; understanding when to play aggressively or conservatively. Despite his size and lankiness, he’s got both good east-west as well as backwards mobility. Pettersson's first pass is almost always on the money and he doesn’t hesitate to curl the puck back into his zone to regroup when necessary. He has above-average offensive instincts in all three zones and his shot is on target and particularly his wrist shot can come at a surprising velocity. A tall player whose frame is ripe for another 40 pounds in the coming years, his developmental curve has also been extremely impressive as he irons out holes in his game at a rapid rate. His confidence and ability to read the game suggest Pettersson has limitless upside at this juncture. Not surprisingly for a player his size, balance is sometimes an issue while pushing and prodding opponents with better core strength. A converted forward, he can be decked at times — with slow response time — and his defensive game is, overall, still in need of improvement.
Pettersson is playing a full-time role for Skelleftea as a 19-year-old in 2015-16 and skated for Sweden at the 2016 World Junior Championship. Still learning the intricacies of playing defense, Pettersson has the skating ability and technical skills to be an effective two-way defender. He is not a punishing player for someone despite his stature but relies on skating, positioning and his passing skill. He plays a style similar to current New Jersey defenseman Adam Larsson though his overall game is not yet at that level.