On May 29th, 2008, Doug Armstrong joined the St. Louis Blues front office, as he was named director of player personnel. It was also known that whenever then current general manager Larry Pleau retired, Armstrong would take over as the GM of the Blues. In 2010, he officially took over as GM, and at first things looked good.
On June 17th, 2010, the Blues acquired goaltender Jaroslav Halak from the Montreal Canadiens. Larry Pleau was still the active GM at the time, but this move had Armstrong written all over it. This was a very solid pick up at the time, as Halak was coming off the best post-season run in his career.