After finishing his collegiate career, Van der Gulik was signed to a two-year entry level contract with the Calgary Flames on May 22, 2006. Attending Calgary's 2006–07 training camp he was then assigned to American Hockey League affiliate, the Omaha Ak-Sar-Ben Knights to start the year. In his first professional season he led all Knights with 80 games and posted 16 goals for 43 points to help Omaha qualify for their first and only playoff appearance. As a rookie, he also led the team with four short handed goals while also setting an impressive franchise record in Plus/minus (+27).