On September 6, 2007, Riley signed a three-year entry-level contract with the Thrashers.

On February 13, 2012, Holzapfel was traded by the Winnipeg Jets to the Anaheim Ducks in exchange for Maxime Macenauer.

[2] He was then immediately assigned to Ducks AHL affiliate, the Syracuse Crunch.

In July 2013, he signed a two-year deal with the Swedish Hockey League club HV71.

[4] After a further third season in Sweden with newly promoted Karlskrona HK in 2015–16 season, Holzapfel left as a free agent to sign a one-year deal with Austrian club, the Vienna Capitals of the EBEL on July 20, 2016.