Career
He is currently playing for the Fort Wayne Komets of the ECHL. He was selected by the Buffalo Sabres in the 4th round (104th overall) of the 2008 National Hockey League Entry Draft. Southorn played four seasons (2006–2010) of major junior hockey in the Quebec Major Junior Hockey League with the Prince Edward Island Rocket. Unsigned from the Sabres, on September 4, 2012, the Elmira Jackals of the ECHL signed Southorn for the 2012-2013 season.
After a short stint in the Elite Ice Hockey League with the Dundee Stars, Southorn returned to the ECHL with the Fort Wayne Komets in the 2013-2014 season.
Having played a single game on loan with the Pirates in the season prior, on July 31, 2014, Southorn signed a one-year AHL contract with the Portland Pirates. In the 2014-2015 season, Southorn was limited by injury an appeared in 26 games with the Pirates for 9 points.
He was loaned to ECHL affiliate, the Gwinnett Gladiators on two occasions, totalling 9 points in just 8 games. On August 5, 2015, unable to secure an AHL contract, Southorn returned on a one-year deal for a second stint with the Fort Wayne Komets of the ECHL.