Cook spent the 2008 AFL season playing with South Adelaide in the South Australian National Football League (SANFL) before making his AFL debut against Collingwood in Round One, 2009.[1][2] He had the opportunity to kick a goal in his first AFL game after taking a contested mark in front of goals late in the game, but missed a relatively easy shot. He played two further games in his debut season, before beginning to secure a more regular berth in Adelaide's first 22 in 2010. Cook kicked his first goal in AFL football in his sixth game, against Melbourne, in Round Three, 2010, a snap around the body with only seconds remaining in the first quarter.