[5] McCormick turned professional in 2003–04 and made his NHL debut with the Avalanche and split the year between the Avs and AHL affiliate the Hershey Bears.

McCormick spent the next four seasons between the Avalanche and the AHL before he found a full-time role with Colorado in 2008–09 playing in an NHL high 55 games and contributing 12 points.

[7] On April 21, 2010, McCormick made his debut with the Sabres in Game 4 of the first round of the Eastern Conference playoffs against the Boston Bruins recording an assist on a goal by Tim Kennedy.

After returning from a lengthy injury with the Sabres during the 2013–14 season, McCormick was included in a trade by Buffalo along with Matt Moulson to the Minnesota Wild in exchange for Torrey Mitchell and draft picks on March 5, 2014.

[12] At the conclusion of the season, McCormick ended his brief stint with the Wild to return to the Sabres as a free agent on a three-year contract on July 1, 2014.

Similar to Pascal Dupuis, despite efforts to medicate and become healthier the complications of the blood clots spreading to McCormick's lungs lead to him retiring at 32 years of age.