The 20-year old was the leading goal scorer for United in 2006/07, and he will be a major loss for the club, but CEO Sam Ciccarello said he or the club would not hold back the youngster in what promises to be a great opportunity.
"It has been wonderful for the club to have brought Nathan to Adelaide and to have been a key to his professional personal development over the past couple of years. We know Nathan is a great talent and feel that he has a big future in front of him," he added.
The signing is a major positive for one of Greece's biggest clubs as it will bolster a strike attack for a team that finished runner-up to Olympiakos last season.
Burns will sign a 2-year deal with the transfer fee reported at being $500,000.
He will most likely join the club just prior to the commencement of the Greek Super League season which is in September, after he finishes his all-important Beijing Olympic duties.