The 31-year-old forward, who netted 95 goals for Hibs and Celtic, has been restricted to two substitute appearances for Alloa Athletic in nearly two years.
Riordan, who had spells in China with Shaanxi Chan-Ba, St Johnstone and Bristol Rovers after leaving Hibernian in 2011, suffered an ankle injury while at Recreation Park, but has regained full fitness after playing five-a-side football and running with his younger brother.
But the Hibs hero has told The Scottish Sun that ‘so much rubbish’ has been said about him that he fears it has hampered his chances.
In an interview with the paper, he said: “I would never claim to be an angel and yes, I’ve had issues in the past but there’s been so much rubbish said about me as well.
“It annoys me that a lot of folk who don’t know me are probably believing most of it.
“That’s possibly putting off managers from giving me a chance.”
Riordan - who had a trial with an unnamed La Liga side during the summer of 2012 - believes he still has plenty to offer a club, adding: “I enjoyed it at Alloa and I appreciated them signing me.
“I’m back to having to keep myself fit again. It’s depressing at times not knowing what’s going to happen - if I’m going to get another club.
“I still believe the right chance will come and I’m ready to give everything I’ve got.”
The Edinburgh-born forward won the PFA Young Player of the Year award during his first stint at Hibs, during which he scored 54 goals in 123 appearances.