After being the #87 overall pick in the NHL draft by the Calgary Flames in 2006, Armstrong played four seasons in the Ontario Hockey League where he put up consistent numbers playing for the Plymouth Whalers and Peterborough Petes. Armstrong then played three seasons in the American Hockey League for the Quad City Flames and Abbotsford Heat and in 2010 he produced his best season accumulating 17 points (8 goals, 9 assists) to go along with 91 penalty minutes.
In 2011-2012 Armstrong shared time between the Utah Grizzlies (37 games) and the Abbotsford Heat (17 games).
