 In 2005 Riewoldt made his senior debut with Clarence at age 16, then went on to play with the club through its finals series including a losing grand final where he kicked four goals.The following year he again played in a senior grand final with Clarence, this time a member of the club's victorious side.He later played and trained with the Tassie Mariners at TAC Cup level and represented his state at the 2006 AFL Under 18 Championships.