4 in the 2009 AFL Rookie draft from South Australian National Football League (SANFL) club North Adelaide.
After played in the opening round 2009 NAB Cup game against the Sydney Swans in which scored three goals, Thompson continued to impress during the preseason and was elevated to the senior squad as a replacement for Jackson Trengove, who was placed on the long-term injury list.
[2] Although he didn't impress like he did during the preseason, Thompson played a satisfactory game in the forward line with 3 kicks, 6 handballs, 3 marks and 1 goal assist.
A week later, Thompson was injured during training when teammate Marlon Motlop accidentally elbowed him in the face, fracturing his eye socket.
Thompson required surgery, with a plate inserted into his eye socket and missed twelve weeks.