Cassell was a highly touted youngster for the Victorian Bushrangers, but injuries limited him to just 2 First Class and 3 One Day games. Cassell's performances in those matches suggested potential, with 7 wickets (at an average of 22.71) in the Pura Cup and 4 wickets in the ING Cup at 22.50. Cassell played all of his state cricket in the 2002-2003 season.
Despite the Bushrangers baring through his constant injury setbacks, 2006/07 proved a bad season for Cassell. When frontline bowlers Shane Harwood, Allan Wise and Gerard Denton all found themselves injured throughout the season, but Cassell remained injured himself, it left the opportunity to Clinton McKay, Darren Pattinson and Grant Lindsay to make the step up to the state side. McKay and Pattison were both offered contracts in the place of Cassell and Brad Knowles.