The 31-year-old has been without a club since he was released by Bristol Rovers a year ago and had agreed to train with SPFL Championship sides Alloa Athletic and Morton.
His most recent opportunity came with the invitation to train with Belgian second division side Antwerp, where former Chelsea striker Jimmy Floyd Hasselbaink is manager. It would have been the second time Riordan agreed to take his career abroad, having previously signed for Chinese club Shaanxi Chan-Ba.
However, Antwerp last night stated that they have ended their interest in the former Hibernian and Celtic forward, citing his reputation for being an insolent character.
"First and foremost, we have six strikers at the club already and we do not intend to lose any of them," said Gunther Hofmans, Antwerp's chairman. "Additionally, Riordan appears to be something of an enfant terrible and has the disadvantage of not having played any league football for over a year. We don't take such risks."