 Although Clark was hit by meningococcal disease the week before the 2005 AFL Draft, Brisbane showed their strong interest, making him their first pick, the ninth player drafted across all clubs and presenting him with their number "1" guernsey; he later made a full recovery from his illness.Clark made an impressive debut for the Brisbane Lions in the first round of the 2006 season against Geelong, converting his first mark and subsequent kick into a goal, but his debut season was significantly hampered by injury problems, in particular osteitis pubis, and only ended up playing a total six games that season.Clark played his first game for the 2007 season in round nine against Collingwood, after overcoming his injury problems.