The Reds announced trials for two foreign players last Friday, but discovered on Monday that one of them, believed to be formerly of Ajax and Valencia, did not appear to exist.
Adelaide United has been left red-faced, with the club admitting it offered a trial to a player who does not exist.
The Reds announced on Wednesday two overseas players had been offered a trial following an extensive search to locate new recruits, one of which was supposed to be former United States youth international Dexter Rosales.
Portuguese striker Fabio Ferreira, formerly of Chelsea, was the other player in question.
Reds football director Michael Petrillo confirmed Rosales was penciled in to train with the A-League club.
"Rosales has been recommended to us," he said. "He's paying his own way here."
However, Adelaide acknowledged on Monday that Rosales had not arrived and the club had been fooled by an elaborate hoax.
"It has been a strange few days with all the speculation around this mystery man - it doesn't look great from our end," a Reds media spokesman told Sportal. "We're not the first club to be given a false lead with a supposed trialist, but other clubs probably just don't promote it to the world like we did."
With Adelaide seemingly one of several clubs to fall victim to the non-existent Rosales, credit must be given to the perpetrators of the elaborate hoax.
'Rosales' caught the eye of Adelaide's scouts with an impressive resume, which listed Dutch champion Ajax and Spanish heavyweight Valencia as former clubs.
The 25-year-old supposedly enjoyed stints with Argentine giant River Plate and Colombian side Club Atletico Junior at youth level, while representing the United States at Under-17, Under-20 and Under-23 level.
However, Rosales' high-profile credentials have no credible sources to verify their legitimacy.
A quick glance at a since-deleted Wikipedia page on Rosales revealed several flaws.
The website stated Rosales was born on July 19, 1987, yet according to several other sources the Miami-born forward also enjoys a birthday on July 7 and July 9.
Image searches of Rosales caused further confusion, with former Ajax and Argentina international Mauro Rosales appearing under the phantom player's name.
Ajax's media department added to the doubts over Rosales' career on Friday by confirming he never played for nor was registered with the Eredivisie side.
"Dexter Rosales was never a contracted player here at Ajax and never was on trial," an Ajax media official said. "I checked Google and saw that there was a [picture] card with the name Dexter Rosales, but that picture of the player in the Ajax kit was Mauro Rosales.
"Mauro was a player from Argentina who was at the club until 2006, but the card and text is not 'Ajax official'. We do not know if Dexter Rosales does or does not exist, but we can confirm that he never was at Ajax."
Valencia also denied the player ever graced the Estadio Mestalla pitch.
"He was not a player of Valencia CF," a press official said.
River Plate added confirmation to the rapid unraveling of Rosales' non-existent career.
"River Plate does not have any registration that says Mr. Rosales was a former player," a media officer said.
Club Atletico, along with US Soccer's governing body and Rosales' supposed high school, did not respond to emails sent last week, while his 'agent' Dimitri Kascovic could not be reached for comment.
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