Tarnasky previously played in the National Hockey League (NHL) with the Tampa Bay Lightning, Nashville Predators and the Florida Panthers.

On September 29, 2008, he was traded to the Nashville Predators in exchange for a conditional sixth-round pick in the 2009 NHL Entry Draft.

After being cut, he signed with the Columbus Blue Jackets, who assigned him to their American Hockey League (AHL) affiliate, the Springfield Falcons.

On July 17, 2012, Tarnasky returned to North America to sign a one-year, two-way contract with the Buffalo Sabres.

On July 6, 2013, Tarnasky left the Sabres as a free agent to sign a one-year contract with the Montreal Canadiens.