2009-10: Andrew O’Brien played junior hockey for the Dixie Beehives in the Central Canadian Hockey League. In 44 games he scored 3 goals with 4 assists and had 45 penalty minutes. The Etobicoke-based team won just 12 games and finished 11th in the 12-team West Division.
2010-11: After passing through the OHL draft, O’Brien signed with Chicoutimi in the Quebec Major Junior Hockey League. He skated in 55 games for the Sagueneens, seeing some time at both forward and defense. He scored 1 goal with 9 assists and was minus-nine with 33 penalty minutes. After finishing fourth in the East, Chicoutimi was swept by Drummondville in the first round of the playoffs. In four playoff games O’Brien scored 1 goal with 1 assist and was an even plus/minus with 6 penalty minutes.
2011-12: O’ Brien was a physical force on the blue line for Chicoutimi while providing timely offense in his second QMJHL season. He was at his best in the playoffs when the Sagueneens made a run to the QMJHL semifinals. In 68 regular season games he scored 8 goals with 21 assists and was plus-two. O’Brien was third on the Sagueneens with 95 penalty minutes. After finishing fifth in the East Division, Chicoutimi knocked off eventual Memorial Cup champion Shawinigan in a second round series and handed Saint John it’s only loss in 17 playoff games. O’Brien scored 1 goal with 9 assists and was minus-one with 31 penalty minutes in 18 playoff games. Though not among the 210 North American skaters listed in Central Scouting’s final rankings, he was selected by Anaheim in the fourth round (108th overall) of the 2012 NHL Draft.
2012-13: Obtained by Rouyn-Nouranda from Chicoutimi in a September 2012 trade, O’Brien skated in 67 games for the Huskies in his over-age season. He scored 2 goals with 16 assists and was +19; finish second on the team with 113 penalty minutes. Rouyn-Noranda finished second in the West Division and reached the playoff semifinals. O’Brien had 4 assists and was +2 with 22 penalty minutes in 14 playoff games. He signed a three-year entry-level contract with Anaheim in April, 2013.
2013-14: O’Brien made his pro hockey debut with the ECHL’s Utah Grizzlies in December after missing the first half of the season due to injury. He played four games with Anaheim AHL affiliate Norfolk in February and was -3 with no points and 4 penalty minutes before being returned to the Grizzlies. O’Brien scored 2 goals with 3 assists and was -7 with 70 penalty minutes in 24 regular season games for Utah. The Grizzlies finished third in the Mountain Division and lost in the first round of the playoffs. O’Brien was -2 with no points nor penalties in three playoff games.
O' Brien is a rugged blueliner who does not back down from a challenge and has the size to back that up. He is a hard-nosed and punishing player with some offensive ability. He needs to continue to polish his play in his own end, pick his spots better, and most importantly, improve his skating.
O’Brien attended training camp with the Ducks and is in his first full season with Anaheim AHL affiliate Norfolk in 2014-15. In the second year of his original three-year entry level contact, O'Brien has provided a physical element on the blueline for the Admirals. Still adjusting to the pace of play at the AHL level, he has shown some progress after struggling in his own end at times early in the year. Long-term O'Brien's size and demeanor, providing he improves his skating and positional play, suggests he can one day be a lower pairing defensive defenseman with an edge at the NHL level.