Glentoran have been stunned by the news that Roy Walker can't become their new manager, just two days after appointing him as successor to Paul Millar.
Walker is unable to take up the post because he does not hold the required Uefa A coaching licence.
The former Crusaders manager would have to complete a Uefa B coaching course before enlisting for the A badge.
"I'm disappointed that presently I am not in a position to take up the offer from Glentoran," Walker told BBC Sport.
Because the Glens are Uefa licence holders their manager, for both European and domestic competitions, must hold an A coaching licence as a minimum.
Walker planned to start working in the post after the club's Uefa Cup games but before the commencement of the domestic campaign.
The requirement for the A badge was not known to the club until after Walker's appointment on Thursday.
A possiblity for Glentoran would be for coach Alan McDonald to take the reigns until Walker gains his coaching badges.
"I'm saddened - I didn't realise the wealth of good feeling there was to me coming to the club."
However, the former Northern Ireland captain, who does possess the Uefa A licence, has stated that he prefers to stay in a coaching role.
Walker hopes to enlist for the initial B badge but it could be a further year before he takes the A course.
"Myself and Alan were excited about working together and we talked about introducing new players but those plans are now scuppered somewhat," Walker added.
"The Glentoran board's view is to work a way around it.
"There are ways you could be creative around it but I want Glentoran to act with integrity and do everything correctly.
"As I understand it I am unable to be Glentoran manager if there's no way round it.
"I'm saddened - I didn't realise the wealth of good feeling there was to me coming to the club.
"I'd like to do something there. I'm more determined to try to make it happen but it is outside my remit."