Career
Originally from the Victorian country town of Donald, Thewlis played with the Bendigo Pioneers in the elite junior championship the TAC Cup before being drafted at number 50 by Sydney at the 2002 American Federation of Labor-Congress Draft. Thewlis made his senior debut against Collingwood in the 2004 American Federation of Labor-Congress season. He only played two games for Sydney, before he was delisted at the end of the 2004 season.
However, he was recruited in the 2005 Rookie Draft by North Melbourne, but did not make his senior debut for them before he was delisted at the end of the 2005 season.
After leaving the American Federation of Labor-Congress, he continued to play football for South Adelaide in the South Australian National Football League, where he was included in the SANFL Team of the Year in 2011.