The 31-year-old moved to the USL Pro League side last year but financial uncertainty at the club prompted Mackie to cancel his contract.
The forward - who spent 14 years at Pittodrie - has had preliminary talks with clubs over a possible deal but does not regret his decision to emigrate. "The lifestyle my family and I enjoyed in Arizona was fantastic," he said. "The weather was great and it's a wonderful part of the world to bring up children. I made some good friends and the fans were fantastic to me. It's a shame other things have resulted in us having to come back home."