The 21-year-old was officially delisted by Port Adelaide on Thursday after playing 11 games in four seasons with the club at the top level.
Johnson was only able to manage the one match in 2019, gathering 12 disposals in the club's round eight match against the Adelaide Crows.
While he was unable to make a major impact at the top level, Johnson was a strong performer for the Port Magpies in the SANFL, kicking 42 goals in his 47 apperances.
Port Adelaide's general manager of football Chris Davies stressed Johnson had been a strong contributor to the club.
“Aidyn has shown signs of what he is capable of throughout his time at the club, and at times this has been of a very high standard,” said Davies.
“No doubt he has been frustrated that he couldn’t produce on a more consistent basis, but he has worked hard and we wish him all the best for the future.”
Davies said that tough decisions had to be made by all clubs as the deadlines for list lodgements approached.
“This is a tough time of the year where we farewell people who have made considerable contributions,” he said.
“We thank both Matt (Broadbent, who was also delisted) and Aidyn for what they’ve done whilst at Port Adelaide and I’m sure our people will join me in wanting the best for them in the next chapter of their careers.”