The doorman on duty may well not recognise a player now firmly in danger of letting his career drift towards a place from which it can't be retrieved.

He is not the first, nor will he be the last, to be accused of squandering his obvious skill. But Riordan's story is all the more significant since he was once seen as Scottish football's greatest hope. Now he risks occupying another role; that of the country's most wretched lost talent.

Exiled from the Celtic first-team, and now banned from Edinburgh nightclubs for two years, Riordan must now hope he can tear the 'not wanted' tag from around his neck before the end of the current transfer window. His latest bid to keep managers alert to his whereabouts seems misguided. Few individuals, save the most idiotic of his friends, will be impressed by another pavement drama.

The news, revealed yesterday, that he had broken a one-year nightclub ban imposed after an incident earlier this summer provided the latest reason to sound a lament for the troubled player. Today, as old Hibernian muckers Kevin Thomson and Scott Brown are named in the Scotland squad for forthcoming games with Macedonia and Iceland, Riordan will follow the routine imposed on him since being banished from first-team training at Celtic. He will head for the 'away' dressing room at Lennoxtown, and prepare to train with the reserves. His relationship with manager Gordon Strachan is said to be "nil" since a press interview in April in which he accused the manager of leaving him out of the team to protect his own credibility.

Even Riordan's fellow team-mates seem out to get him. The day before that interview was published Celtic slumped to a 1-0 home defeat against Motherwell, a loss which seemed to sink their title defence hopes. Strachan's position looked shakier than ever, and doubts persisted about his own desire to continue. If Riordan had based his decision to sound-off on the likelihood of Strachan not being around much longer, then it looked a canny move.

But Riordan's outburst appeared to spur the team on, and thereby helped strengthen Strachan's position at the club. Celtic have not lost a competitive match since. Riordan, for his part, has seen action only in a friendly against Manchester City, and in a team which included so many unwanted figures they might have been sent out to play with bells tied around their necks. Fellow pariah Thomas Graveson also played that day, and has since moved on.

Riordan, however, is left to sit and stew. The only good news of late has been the extension to the transfer window. He and his agent Jim McArthur now have an extra 24 hours to find a way out of Celtic. The club have not, so far, been persuaded to treat his case with sympathy. They feel they have earned the right to play hard-ball. Riordan has banked a sizeable wage since joining Celtic from Hibs. If not reimbursed by more than the £400,000 offered by Burnley earlier this year, the club appear content to retain the right to control the player's movements, at least until the end of the season.

Riordan, meanwhile, has found the exclusion zone around the Celtic first team harder to penetrate than the one surrounding the nightclubs in his home city. He hasn't played a competitive game since being thrown on towards the end of Celtic's Scottish Cup loss to Aberdeen in March. It's likely he has already made his last appearance in a hooped shirt. Even the current injury crisis which has laid low the team's principal strikers in Scott McDonald and Jan Vennegoor of Hesselink has led to no mention of Riordan, with an Old Firm clash looming this weekend. Indeed, it has been so long since he last started a match that those opponents no longer exist. This came back in January, against Gretna.

Riordan turns 26 in January, and, with Celtic unlikely to opt to keep him for another year, is free to speak to other clubs from December. His reputation as a scorer of great goals may have survived his Celtic stay, but, worryingly, a more powerful impression remains that of a trouble-maker. Riordan said in the Spring that his delinquent days were in the past. He pointed out that he had kept his nose clean since December 2006. Even then he was found not guilty after being charged with assault on a barman.

These latest scrapes are not nearly as serious. An attempt to enter a nightclub which resulted in a heated exchange with a bouncer is a scenario many are familiar with. Less forgivable was an attempt to break his curfew soon after.

This latest controversy cannot have come at a worse time. He has long since given up hope of changing Strachan's opinion, but then it isn't him he needs to impress now, it is other managers. It's hard to prove yourself when reserve team football is your only platform. Even the most level-headed person would have been tested by what Riordan has endured at Celtic. But, for the sake of his career, the player must rise above his perceived grievances. Being barred from a few nightclubs isn't one of those. In fact, it might just prove a saving grace.