[2] He earned WHL East First Team All-Star honours, along with teammates Brandon Kozun and Brett Sonne and a nomination for the Bill Hunter Memorial Trophy as the league's top defenceman, opposite Jonathon Blum of the Vancouver Giants.

[7] After spending his first eight professional seasons with the Thrashers/Jets franchise, Postma left as a free agent in agreeing to terms with the Boston Bruins on a one-year, $775,000 contract on July 1, 2017.

As a free agent from the Bruins, Postma opted to halt his North American career, agreeing to a one-year contract with Russian champions, Ak Bars Kazan of the Kontinental Hockey League (KHL), on August 15, 2018.

Moving to continue his career in Switzerland, after a successful tryout, Postma joined HC Lugano of the National League (NL) on a one-year deal on November 6, 2019.

On December 8, 2020, Postma belatedly joined Austrian club, EC KAC of the ICEHL, as a free agent on an initial one-year contract.