The World Game understands Choi, who has drawn attention to himself recently with a series of outstanding performances in the FFA Cup and NSW NPL, will be an injury replacement for Marcelo Carrusca for the start of the A-League season.
Carrusca, one of Adelaide's five visa players, is still having problems with a foot injury and is expected to remain on the sidelines for a number of the Reds opening matches.
Adelaide have other players on the injured list, including Jordan Elsey, who is out for the season with a torn ACL, and Michael Marrone, who is not expected to play until December because he is still recovering from a torn Achilles tendon sustained in the grand final win in May.
But Choi would be unable to replace either of those players at this stage because while he is an Australian resident, he is not yet an Australian citizen and can only join an A-League club as either a visa player or a replacement for an injured visa player.
The 21-year-old, who scored a stunning, 70-metre goal in Blacktown's FFA Cup round of 32 win over Sydney United 58, is in the process of becoming an Australian citizen.
Negotiations between Adelaide and Choi's management have been ongoing recently, but no contract has been signed yet because that would prohibit Choi from turning out for Blacktown in their huge FFA Cup clash with the Sky Blues.
Providing he gets through that game without injury himself, a deal between Adelaide and Choi is expected to be quickly formalised.
Depending on when his citizenship comes through, Choi could presumably then sign a season-long contract as an injury replacement for Elsey.
Clearly, Adelaide see Choi as a very promising prospect and are keen to beat other clubs to get him on their books. It is understood several other A-League clubs were chasing him as well.
Choi told the Blacktown Sun newspaper on Tuesday that he expects to be confirmed as an Adelaide player very soon.
"I haven’t signed yet, but I hope it should be done in the next few days," he said.
Mark Crittenden, the Blacktown coach who steered the team to win the National Premier Leagues title last October and the NSW NPL grand final earlier this month, is gaining a tremendous reputation for his ability to prepare young players for the step up to the A-League.