Stanley was recruited from West Adelaide with pick 47 in the 2008 AFL Draft. He played little football growing up but impressed with South Australia in the AFL Under 18 championships and in two senior games for West Adelaide.
In 2010 Stanley played in St Kilda's opening 2010 NAB Cup match against Collingwood, kicking one goal. On 23 May 2010, he made his official debut in Round 9 of the home and away season in which St Kilda defeated the West Coast Eagles at Subiaco. He had nine disposals, three marks, four kicks and five handballs. Rhys Stanley played seven games for St Kilda in 2010, with a toal of 53 disposals and four goals. Between rounds 9 and 14, Stanley played in a tall forward role, helping St Kilda to win all six of these games while the captain, Nick Riewoldt, recovered from a hamstring tear.