Holzapfel played
major junior hockey for the
Moose Jaw Warriors of the
Western Hockey League (WHL). He was drafted by the
Atlanta Thrashers at the
2006 NHL entry draft, chosen 43rd overall. On September 6, 2007, Riley signed a three-year entry-level contract with the Thrashers. In 2008, he played for Canada in the
IIHF World U20 Championship where Canada went on to win gold in a 3-2 victory over Sweden. On February 13, 2012, Holzapfel was traded by the
Winnipeg Jets to the
Anaheim Ducks in exchange for
Maxime Macenauer. He was then immediately assigned to Ducks AHL affiliate, the
Syracuse Crunch. He signed a one-year, two-way contract as a free agent with the
Pittsburgh Penguins on July 1, 2012, but spent the season in
AHL with
Wilkes-Barre/Scranton Penguins. In July 2013, he signed a two-year deal with the
Swedish Hockey League club
HV71. 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. After leading the Capitals with 53 points in 54 games in the
2016–17 season, and contributing with 23 points in just 12 post-season games, he received the Ron Kennedy Trophy as the league's Most Valuable Player. ==Career statistics==